* 


DATE  DUE 

j 14 

1 P 2007 


Special  Elditioi^  members  of  the 
National  Fire  Protection  Association 


mr 


m 


INCORPORATED  1901 


ESTABLISHED  AND  MAINTAINED  BY  THE 

National  Board  of  Fire  Underwriters 

FOR  SERVICE— NOT  PROFIT 


a 


Report  on 

INTERIOR  BUILDING  CONSTRUCTION 


m 


Consisting  of 

METAL  LATH  AND  GYPSUM  PLASTER 
ON  WOOD  SUPPORTS 


Jointly  submitted  by 

Associated  Metal  Lath  Manufacturers, 
Chicago,  111. 

and 

National  Lumber  Manufacturers  Association, 
Chicago,  111.  Washington,  D.  C. 


Report  on 

Interior  Building  Construction 

Consisting  of 

Metal  Lath  and  Gypsum  Plaster  on 
Wood  Supports 

Jointly  Submitted  by 

Associated  Metal  Lath  Manufacturers 
Chicago,  111. 

and 

' { 

National  Lumber  Manufacturers  Association 
Chicago,  111.  Washington,  D.  C. 


ESTABLISHED  AND  MAINTAINED  BY  THE 

National  Board  of  Fire  Underwriters 

FOR  SERVICE— NOT  PROFIT 

PRINCIPAL  OFFICE  AND  TESTING  STATION 

207  East  Ohio  Street,  CHICAGO,  ILL. 

Aug.  10,  1922 
Retardant  No.  1355 


Copyright  1922,  by  Underwriters’  Laboratories 


■JvS  i Mor.  '7''' 


C-'  t 


PREFACE 

The  investigation  described  herein  was  inaugurated  and 
largely  carried  out  by  the  late  W.  C.  Robinson,  Vice-President 
and  for  20  years,  Chief  Engineer  of  Underwriters’  Laboratories. 
The  signer  of  this  report  and  others  of  Mr.  Robinson’s  associ- 
ates in  the  staff  desire,  in  presenting  the  report,  to  acknowledge 
his  large  share  in  the  work  it  describes.  Mr.  Robinson,  for  sev- 
eral years  before  his  death  (July  31,  1921),  had  in  mind  the 
feasibility  of  designing  buildings  of  frame  and  of  ordinary  con- 
struction, especially  those  intended  for  residence  and  similar 
light  occupancies,  where  only  the  common  fire  hazards  are  found 
and  where  the  bulk  of  the  inflammable  contents  is  small,  so  that 
they  would  be  semi-fire-resistive.  It  was  his  sincere  belief  that 
utilization  of  suitable,  readily  available  materials  and  methods 
of  design  was  not  only  possible  but  entirely  practicable  and  this 
without  material  additional  cost  of  buildings  and  without  a need 
for  educating  the  American  people  to  live  or  work  under  new 
or  strange  conditions.  When  economic  considerations  do  not 
require  or  justify  fire  resistive  construction  throughout,  the  ap- 
plication of  a certain  few  fundamentals  of  fire  protection  will  do 
much  to  reduce  the  large  cost  in  life  and  in  property  of  the 
present  national  fire  waste,  (approx.  20,000  lives  and  $500,000,- 
000.00  annually).  One  such  fundamental  is  to  confine  incipient 
fire  to  the  room  or  other  space  of  its  origin.  The  use  of  ma- 
terials and  methods  having  a definite  classification  as  Fire  Re- 
tardants, (such  as  the  constructions  described  herein  and  others 
now  rated,  or  presently  to  be  rated)  when  they  are  selected 
according  to  the  probable  severity  6f  fire  exposure,  is  a logical 
means  of  observing  this  fundamental. 


I 


TABLE  OF  CONTENTS 


Page 

INTRODUCTORY  1 

SECTION  I 

Walls  and  Partitions,  Bearing  and  Non-Bearing 

DESCRIPTION  4 

General  Character  4 

Use 5 

Description  of  Parts ! 6 

PLAN  OF  INVESTIGATION 8 

EXAMINATION  AND  TEST  RECORD 9 

Installation  Test  9_ 

Fire  Endurance  Test  No.  1 14 

Fire  Endurance  Test  No.  2 23 

- Fire  and  Hose  Stream  Test 34 

Supplemental  Fire  and  Hose  Stream  Tests 41 

SECTION  II 

Floor  and  Ceiling  Construction 

DESCRIPTION  46 

General  Character  46 

Use  47 

Description  of  Parts 47 

PLAN  OF  INVESTIGATION 47 

EXAMINATION  AND  TEST  RECORD 48 

Installation  Tests  49 

Fire  Endurance  Test 57 

Fire  and  Hose  Stream  Test  62 

Excess  Load  Test.„ 64 

SECTION  III 

SERVICE  RECORD  67 

SUPERVISION  OF  PRODUCT  BY  UNDERWRITERS’ 

LABORATORIES  67 

CONCLUSIONS  67 

Practicability 67 

Durability  68 

Strength  68 

Fire  Retarding  Properties 69 


TABLE  OF  CONTENTS— Continued 


SECTION  IV 

Pa^e 

APPENDIX  I 74 

Tests  on  Wood  Joist  Floor  Construction — Finished  with  Metal 

Lath  and  Portland  Cement  Plaster 74 

APPENDIX  II  94 

Transverse  Load  Tests  on  Metal  Lath  and  Gypsum  Plaster  on 

Wood  Supports  94 

APPENDIX  III  96 

Specifications  for  Preparation  and  Installation  of  Metal  Lath 

and  Gypsum  Plaster  on  Wood  Supports 96 

APPENDIX  IV  : ’ 100 

Claims  Made  by  Submittors 100 

Principle  of  Design 100 

Durability  102 

Economies  103 

Safety  After  Charring  104 

Minimum  Metal  Lath  Specifications  105 

APPENDIX  V 106 

Standard  Equipment  and  Panels  for  Partition  Tests 106 

APPENDIX  VI  : 110 

Standard  Equipment  for  Tests  of  Floors  and  Ceiling  Finish 110 

APPENDIX  VII 113 

Standard  Specifications  for  Fire  Tests  of  Materials  and  Con- 
struction   113 

SECTION  V 


RECOMMENDATIONS 


117 


■4.’ 


Digitized  by  the  Internet  Archive, 
in  2017  with  funding  from 

University  of  Illinois  Urbana-Champaign  Alternates 

/ 


/ 


https://archive.Org/details/repOrtOninteriorOOunde 


AOCNCII 


E-PRESIOENTS, 


W H MERRILL.  President 
DANA  PIERCE.  U 
A R SMALL.  i 
D B.  ANDERSON,  secretary 
L B HEADEN.  Treasurer 


CHICAGO. 
NEW  YORI- 

M yV)  BOSTON,  e 

(\VV  INCORPORATED  1901  ^ 

established  AND  MAINTAINED  BYTHE 


CHICAGO.  207  East  Ohio  Strcet 
NEW  YORK.  25  CitV  Haul  Place 
BOSTON.  67  Milk  STueeT 
PITTSBU  RGH.  324  Pourth  Avenue 
SAN  FRANCISCO 


ESTABLISHED  AND  MAINTAINED  BYTHE 

National  Boari)  of5in»  UnDcnpritmi 

FOR  SERVICE-NOT  PROFIT 

207  EAST  OHIO  STREET.  CHICAGO 


Retardant  No.  1355 

August  10,  1922 

Report  on 

INTERIOR  BUILDING  CONSTRUCTION 

consisting  of 

Diamond  Mesh  Expanded  Metal  Lath  and  %-in.  (three-caat) 
Fibered  or  Sanded  Gypsum  Plaster,  mounted  on  Wood  Sup- 
ports, for  Bearing  and  Non-Bearing  Walls  and  Partitions  and 
Wood  Joist  Floors  in  Buildings  of  Frame  or  Ordinary  Con- 
struction suitably  fire  stopped. 

Associated  Metal  Lath  Manufacturers 

and 

National  Lumber' Manufacturers  Association. 

Joint  Submittors. 


INTRODUCTORY 

In  1918  the  Associated  Metal  Lath  Manufacturers,  an  or- 
ganization of  a number  of  producers  of  metal  lath,  and  the 
National  Lumber  Manufacturers  Association,  arranged  for  a 
series  of  tests  at  Underwriters’  Laboratories  to  determine  the 
fire  retarding  value  of  a building  construction  utilizing  the  prod- 
ucts of  the  members  of  the  two  associations.  A series  of  tests 
was  first  made,  in  which  test  results  were  secured  which  were 
judged  not  comparable  to  the  best  possible  results  obtainable 
with  the  submittors’  products.  Accordingly,  other  tests  were 
arranged  and  made  in  1922  with  samples  in  which  either  sanded 
or  fibered  gypsum  plaster  was  used  instead  of  portland  cement 


1 


and  sand  plaster.  It  is  largely  upon  the  basis  of  the  results  of 
these  later  tests  that  the  conclusions  and  recommendations  of 
this  report  are  drawn,  although  much  valuable  data  was  obtained 
in  the  first  series  of  tests,  the  character  and  results  of  which  are 
briefly  outlined  and  illustrated-  in  Appendix  I. 

In  the  autumn  of  1921  the  Fire  Council  of  Underwriters’ 
Laboratories  endorsed  a recommendation  of  the  Protection  En- 
gineers to  the  effect  that  future  work  on  fire  retardants  should 
be  upon  the  basis  of  the  Standard  Specifications  for  Fire  Tests 
of  Building  Materials  and  Construction  regularly  adopted  as  a 
tentative  American  Standard  by  the  American  Engineering 
Standards  Committee.  The  test  practices  outlined  in  these 
standard  specifications  for  fire  tests  are  substantially  those 
which  have  been  employed  by  Underwriters’  Laboratories  for  a 
number  of  years.  Accordingly,  the  classifications  recommended 
at  the  conclusion  of  this  report  are  based  upon  nationally  stand- 
ardized test  methods  and  also  upon  methods  of  analysis  of  re- 
sults practically  identical  with  those  employed  in  the  classifica- 
tion of  a long  series  of  fire  retarding  devices,  designs,  and  con- 
structions previously  reported  upon  by  Underwriters’  Labora- 
tories. 

These  Standard  Specifications  for  Eire  Tests  of  Building  Ma- 
terials and  Construction  are  given  in  Appendix  VII. 

This  report  deals  with  interior  wood  studded,  bearing  and 
non-bearing,  walls  and  partitions  and  with  a wood  joist  floor  con- 
struction protected  by  expanded  metal  lath  and  gypsum  plaster 
finish,  developing  mainly  the  fire  retardant  properties  secured 
by  the  use  of  these  materials. 

This  report  is  divided  into  the  following  sections : 

SECTION  I 

Interior  building  construction  for  bearing  and  non-bearing 
walls  and  partitions  consisting  of  expanded  metal  lath  and  gyp- 
sum plaster  on  wood  supports. 

SECTION  II 

Interior  floor  and  ceiling  construction  as  a fire  retardant 
consisting  of  expanded  metal  lath  and  gypsum  plaster,  on 
wood  joists  with  wood,  rough  and  finished  flooring. 

SECTION  III 

The  conclusions  drawn  from  the  investigation  and  tests  made 
as  described  in  Sections  I and  II,  together  with  statements  as 
to  Service  Record  and  methods  of  follow-up  applicable. 


2 


SECTION  IV 

This  part  of  the  report  consists  of  several  appendixes,  as 
follows : 

Appendix  I — Wood  joist  floor  construction  protected  by 
metal  lath  and  portland  cement  plaster. 

Appendix  II — Transverse  Load  Tests  on  wood  studs  pro- 
tected by  metal  lath  and  'gypsum  plaster  construction. 

Appendix  III — Specifications  for  application  of  metal  lath 
and  gypsum  plaster  construction  on  wood  supports. 

Appendix  IV — Claims  made  by  the  Submittors. 

Appendix  V — Standard  equipment  and  panels  for  tests  of 
wall  and  partition  constructions. 

Appendix  VI — Standard  equipment  for  tests  of  floor  and 
ceiling  constructions. 

Appendix  VII — Standard  Specifications  for  Fire  Tests  of 
Materials  and  Construction. 

SECTION  V 

The  recommendations  made  by  the  Staff  to  the  Fire  Council 
of  Underwriters’  Laboratories  covering  classification  and  list- 
ing of  the  constructions  reviewed. 


SECTION  I 

Retardant  No.  1355 

INTERIOR  BUILDING  CONSTRUCTION 

FOR 

Bearing  and  Non-Bearing  Walls,  and  Partitions 

consisting  of 

Metal  Lath  and  Gypsum  Plaster  on  Wood  Supports 


INTERIOR  FINISH  FOR  WALLS  AND  PARTITIONS 
AS  A FIRE  RETARDANT 

As  regards  its  influence  on  the  spread  of  fire  within  build- 
ings, interior  wall  and  partition  finish  should  possess  fire  re- 
sistive properties  providing  a barrier  to  the  spread  of  fire  within 
buildings  and  preserving  the  structural  integrity  of  buildings 
under  fire  conditions,  and  should  retain  these  properties  under 
the  wear  and  tear  and  other  service  conditions  incidental  to  the 
use  of  buildings.  These  requirements  necessarily  involve  all  of 
the  parts  that  are  assembled  to  finish  or  to  ef¥ect  the  subdivi- 
sion of  buildings  and  their  floor  areas  into  the  units  required 
by  the  occupancy,  including  the  frames,  doors  and  sash  at 
necessary  openings. 

This  report  deals  with  the  solid  or  unbroken  portions  of 
partitions  or  walls,  bearing  and  non-bearing,  of  representative 
metal  lath  and  gypsum  plaster  construction  on  wood  studs,  de- 
veloping mainly  the  fire  retardant  properties  secured  by  the 
use  of  these  materials. 

DESCRIPTION: 

GENERAL  CHARACTER 

The  construction  forming  the  subject  of  this  section  of  the 
report  consists  of  bearing  and  non-bearing  room  and  corridor 
partitions  of  the  hollow  type  and  wood  stud,  metal  lath  and 
fibered  gypsum  plaster  pattern. 

Th_ese  partitions  or  walls  consist  of  the  studs,  the  sills,  or 
foot  plates,  the  cap  plates,  the  fire  stops,  the  frames,  the  trusses, 
the  doors,  the  sash,  the  metal  lath,  its  fastenings,  the  special 
supports,  the  plaster  coatings,  the  grounds,  the  metal  corner 
beading  and  the  standing  finish  that  may  be  used  on  the  sur- 


4 


DESCRIPTION 


- w^.[TI 


faces.  The  construction  is  approximately  5 in.  or  7 in.  in 
thickness,  depending  on  the  size  of  the  studs,  and  may  be  made 
oi  any  length  and  in  heights  up  to  and  including  25  ft.  The 
average  height  does  not  exceed  12  ft. 

In  plain  constructions  the  wood  studs  are  spaced  12  or  16  in. 
on  centers  and  are  so  arranged  at  the  corners  and  at  junctions 
between  partitions  and  with  walls  that  solid  corners  and  angles 
are  provided  for  attaching  the  lath  at  these  points.  In  curved 
constructions  the  studs  are  set  and  spaced  according  to  the 
radius  of  curvature.  They  are  doubled  around  all  openings. 
The  studs  extend  from  the  sills  at  the  floor,  or  from  girders,  or 
from  the  plates  of'  partitions  or  walls  directly  underneath  to 
the  cap  plates  at  the  top. 

The  sills  and  plates  extend  across  the  studs  at  the  bottom 
and  top,  respectively.  The  sills  rest  on  the  under  or  rough 
floor  and  are  used  when  the  studs  do  not  extend  through  the 
floor  joist  and  rest  on  girders  or  the  plates  directly  underneath. 
The  fire  stops  are  located  between  the  studs  at  floor  levels.  The 
trusses  are  employed  in  bearing  constructions  and  are  used 
above  openings  in  excess  of  3 ft.  in  width  and  where  unusual 
loads  come  over  the  opening.  The  frames  for  the  doors  and 
sash  are  centered  in  the  studding  and  are  nailed  to  studs. 

The  sheets  of  lath,  on  each  side  of  the  studding  are  fastened 
with  staples  or  with  nails  driven  part  way  in  and  bent  over  to 
the  studs  or  supports  and  are  placed  in  horizontal  courses  with 
edges  overlapping.  At  joints  with  side  walls  and  ceilings  the 
lath  is  bent  to  a right  angle  and  extended  to  overlap  the  ad- 
joining surface  for  about  6 inches.  A tie  wire  is  used  at  over- 
lapping edges  of  the  lath  between  supports  and  in  attaching  the 
lath  at  coves.  Special  supports  are  used  at  coves,  for  extra 
nailing  bases  wherever  the  framing  is  irregular  and  at  fixture 
outlets. 

The  plaster  coatings  completely  cover  all  lathed  surfaces  and 
extend  to  the  floors  and  back  of  all  standing  finish  up  to  the 
rougher  framing  at  the  openings.  The  grounds  are  nailed  to  the 
framing  at  the  openings  and  cemented  to  the  scratch  coat  of 
plaster  at  other  points.  The  metal  corner  beading  is  nailed  to 
the  vertical  supports  at  outside  angles.  The  standing  finish  is 
nailed  to  the  grounds  and  supports  and  is  in  direct  contact  with 
the  plastered  surfaces  where  it  is  applied. 

USE 

This  construction  is  regularly  used  for  bearing  and  non- 
bearing partitions  of  walls  in  buildings  in  which  wood  studding 
is  employed  and  for  studded  exterior  walls  except  for  the  ex- 
terior finish.  It  is  also  used  on  masonry  walls  where  furring  is 
employed. 


5 


WALLS  AND  PARTITIONS 


DESCRIPTION  OF  PARTS 

Studs — The  studs  may  be  of  any  wood  used  in  buildings  of 
frame  or  ordinary  construction  that  is  sound  and  free  from  de- 
fects that  seriously  affect  alignment  of  the  studs  or  impair 
their  strength  or  durability. 

The  studs  are  usually  nominally  2 by  4 in.,  but  they  may  be 
2 by  2 in.,  2 by  6 in.  or  larger.  The  size  of  the  studs  and  their 
spacing  is  largely  dependent  on  the  loads,  the  heights  and  the 
location  of  openings. 

Sills  and  Plates — The  sills  and  plates  are  usually  made  of 
the  same  size  and  kind  of  wood  as  the  studs.  Single  sills  and 
l)lates  are  usually  employed  for  non-bearing  construction.  Dou- 
ble sills  and  plates  may  be  used  for  bearing  partitions  or  walls. 

Fire  Stops — Fire  stops  at  the  floor  levels  may  consist  of 
metal  lath  baskets  filled  with  incombustible  materials  and  com- 
pletely filling  the  spaces  between  joists  and  studs  to  a height 
of  4 in.  above  the  floor  level  or  may  be  tightly  fitted  wood  blocks 
with  a nominal  thickness  of  2 in.  or  more.  The  wooden  braces 
or  bridging  between  studs  at  the  middle  of  the  studs  serve  as 
fire  stops  as  well  as  to  increase  the  stability  or  lateral  stiffness 
of  the  assembly. 

Trusses — The  trusses  are  mostly  used  in  bearing  partitions 
and  walls,  are  made  of  the  same  size  and  kind  of  wood  as  the 
studs,  and  consist  of  diagonal  struts  between  the  plates  and  the 
heads  of  the  framing  at  openings.  They  are  used  to  transmit  the 
loads  to  the  double  stud  supports  at  the  sides  of  the  openings. 
The  studs  are  cut  in  between  the  diagonals  over  the  opening. 

Frames,  Doors  and  Sash — These  members  may  be  made  of 
any  kind  of^  seasoned  wood  and  in  any  design  used  for  interior 
finish.  The  frames  are  securely  nailed  to  the  double  studs  at 
the  top  and  sides  of  the  openings  and  are  also  held  in  place  and 
finished  by  the  casing  on  each  side  of  the  partitions.  The  doors 
and  sash  are  mounted  in  the  frames  with  ordinary  hardware 
in  the  usual  manner. 

When  metal  frames  and  doors  and  sash  glazed  with  wired 
glass  are  employed  in  these  partitions  the  metal  members  are 
installed  and  attached  in  essentially  the  same  manner  as  the 
wooden  members. 

Metal  Lath — The  lath  is  of  the  expanded  metal  type  and  the 
'yg-in.  diamond  mesh  pattern  and  is  made  from  No.  26  U.  S. 
gauge  open  hearth  sheet  steel.  The  finished  sheets  are  18  and 
24  in.  wide  and  96  in.  long,  are  coated  with  asphaltum  paint 
and  weigh  2.5  lbs.  per  sq.  yd. 

The  lath  is  furnished  in  bundles  containing  9 to  15  sheets 
or  16  to  20  sq.  yds.  per  bundle  fof  the  18  and  24-in.  widths,  re- 
spectively. ' ^ 


G 


DESCRIPTION 


Nails,  Staples  and  Tie  Wire — The  nails,  when  used,  are  4 
penny  l^^-in.  nails  and  are  driven  partly  in  and  bent  over. 

The  staples  are  1^-in.  No.  14  W.  & M.  gauge  round  top 
plain  wire  staples  with  pointed  ends. 

The  tie  wire  is  No.  18  U.  S.  gauge  soft  annealed  wire. 

V Plaster  Coatings — The  plaster  coatings,  aggregating  about 
^ in.  in  thickness,  consist  of  a scratch  coat  and  a brown  coat 
of  a standard  brand  of  fibered  or  sanded  gypsum  plaster  and 
sand,  and  a finish  coat  of  lime  putty  gauged  with  gypsum 
plaster. 

The  scratch  coat  is  composed  of  one  part  by  volume  of  gyp- 
sum plaster  and  one  part  by  volume  of  clean,  sharp,  dry  sand. 
The  brown  coat  is  composed  of  one  part  by  volume  of  gypsum 
plaster  and  two  parts  by  volume  of  clean,  sharp,  dry  sand.  The 
finish  coat  is  composed  of  three  parts  lime  putty  by  volume  and 
one  part  by  volume  of  dry  calcined  gypsum  plaster.  The  outer 
surface  of  the  plaster  coatings  is  finished  smooth  and  true. 

Grounds — The  grounds  consist  of  narrow  wooden  strips  ^ 
in.  thick  at  the  framing  around  openings  and  standard  round 
metal  spot  grounds  at  all  other  points.  The  spot  grounds  are 
of  such  thickness  that  their  outer  faces  finish  ^ in.  from  the 
supports  and  are  provided  with  metal  backing. 

Metal  Corner  Beading — The  metal  corner  beading  may  be  of 
any  of  the  forms  ordinarily  employed  for  the  protection  of  plas- 
ter corners  at  outside  angles. 

Standing  Finish — The  standing  finish  may  consist  of  any  or 
all  of  the  following  items : baseboards,  wainscoating,  casings, 
chair  rails,  moulding  or  finished  woodwork  that  is  attached  to 
the  partitions  after  the  plastering  is  completed.  These  mem- 
bers may  be  made  of  any  kind  of  seasoned  wood  and  be  of  any 
design  used  for  interior  finish,  and  are  securely  nailed  to  the 
grounds,  studs  or  rougher  framing. 

Where  desired  the  standing  finish  may  be  of  metal. 

INSTALLATION 

Complete  specifications  for  preparation  and  application  of 
metal  lath  and  gypsum  plaster  construction  on  wood  supports 
are  given  in  Appendix  III. 

CLAIMS  MADE  BY  THE  SUBMITTORS 

The  claims  as  set  forth  by  the  submittors  relative  to  this 
construction  are  given  in  Appendix  IV. 

OBJECT  OF  THE  INVESTIGATION: 

The  object  of  this  investigation  was  to  ascertain  from  the 
fire  protection  viewpoint  the  value  of  the  construction  described 


7 


WALLS  AND  PARTITIONS 


and  to  determine  its  classification  under  the' ‘'Standard  Specifi- 
cation for  Fire  Tests  of  Materials  and  Construction/’  as  given 
in  Appendix  VII. 

PLAN  OF  INVESTIGATION: 

The  general  features  of  the  investigation  covered  the  sub- 
jects of  Practicability,  Durability,  Strength  and  Uniformity  as 
well  as  of  Resistance  to  Fire  and  to  Fire  and  Hose  Streams. 

In  considering  these  subjects  the  features  of  Handling  and 
Shipping,  Preparation  for  axid  actual  Installation,  Maintenance, 
Wear  and  Tear,  Moisture,  Heat,  Flame  Resistance  and  Heat 
Resistance  were  severally  studied.  Data  covering  these  features 
and  properties  were  obtained  during  the  preparation  of  speci- 
mens for  tests,  during  the  actual  conduct  of  tests  and  in  studies 
of  the  specimens  and  their  units  after  tests. 

THE  FOLLOWING  TESTS  WERE  MADE 

Installation  Test. 

Two  Standard  Fire  Endurance  Tests. 

Standard  Fire  and  Hose  Stream  Test. 

Supplemental  Fire  and  Hose  Stream  Tests. 

The  procedures  employed  in  these  tests  and  the  performance 
of  the  specimens  in  the  tests  are  reported  in  the  following  sec- 
tion entitled  Examination  and  Test  Record. 


8 


EXAMINATION  AND  TEST  RECORD: 

INSTALLATION  TEST 

This  test  was  made  in  connection  with  the  installation  of 
specimens  in  the  panels  for  the  Fire  Endurance  Tests  and  the 
Fire  and  Hose  Stream  Test.  These  panels  and  the  frames  in 
which  they  are  mounted  for  tests  are  described  in  Appendix  V 
hereto. 

Three  test  panels  were  installed  in  accordance  with  the 
method  advocated  by  the  Submittors  and  as  detailed  in  Appen- 
dix III,  Specifications  for  Preparation  and  Installation  of  Metal 
Lath  and  Gypsum  Plaster  Construction  on  wood  supports. 

The  following  is  a list  of  the  material  used  in  the  installation 
of  the  panels  and  in  supplementary  tests. 

Bill  of  Material — • 

5 bundles  of  No.  26  U.  S.  gauge  ^-in.  diamond  mesh  lath, 

sheets  24  in.  wide  and  96  in.  long. 

20  pounds  of  l^^-in.  No.  14  W.  & M.  gauge  wire  staples, 

6 pounds  of  No.  18-gauge  soft  annealed  tie  wire, 

130  spot  grounds, 

8 bags  of  extra  fibered  gypsum  plaster, 

8 bags  of  hair  fibered  gypsum  plaster,. 

6 bags  of  regular  fibered  gypsum  plaster, 

I bag  of  dry  calcined  gypsum  plaster, 

4 bags  of  hydrated  lime, 

3^  yards  of  plastering  sand, 

12  pieces  of  9-in.  Southern  Yellow  Pine  baseboards, 

12  pieces  of  3^-in.  Southern  Yellow  Pine  chair  rails, 

12  pieces  of  1^-in.  Southern  Yellow  Pine  picture  moulding. 

METHODS 

The  framework  or  studding  was  mounted  .in  the  panel 
frames  and  the  wood  trim  was  applied  by  ex])erienced  workmen 
of  the  Laboratories’  force.  The  Submittors  furnished  the  work- 
men for  installing  the  metal  lath,  the  spot  grounds,  and  the 
plaster  coatings. 

The  following  observations  and  comments  relate  to  the  fea- 
tures and  properties  listed  in  the  foregoing  Plan  of  Investi- 
gation. 

RESULTS 

Preparation  and  Installation  of  Lath — The  bundles  of  lath 
were  opened  and  the  sheets  removed  and  carried  to  the  panels 
by  one  man.  The  sheets  required  no  special  preparation  except 
cutting  to  the  proper  length  and  bending  to  return  on  the  ma- 
sonry at  the  side  and  upper  edges  of  the  panels.  The  bundles 
and  sheets  were  easily  handled.  The  sheets  were  cut  by  ordi- 
nary snips  and  bent  over  a straight  edge  without  difficulty. 


9 


WALLS  AND  'PARTITIONS 


The  lath  was  applied  to  both  sides  of  each  of  the  panels  by 
one  lather.  The  sheets  were  placed  in  position  in  horizontal 
courses  and  attached  by  staples  driven  into  the  studs,  beginning 
at  the  top.  Each  sheet  was  adjusted  so  that  its  upper  edge 
overlapped  the  lower  edge  of  the  preceding  sheet  >4  to  ^ in., 
was  held  in  position  by  a few  staples  until  in  proper  position  at 
all  points  and  then  fastened  by  wire  staples  spaced  4 to 

6 in.  on  each  support.  Each  course  consisted  of  one  full  sheet 
and  a part  of  another.  The  edges  and  ends  were  bent  so  as  to 
return  on  the  brickwork  from  2 to  6 in.  at  the  sides  and  top  and 
bottom  of  the  panels,  staples  being  driven  into  the  mortar  joints 
at  6 to  12-in.  intervals.  The  vertical  joints  between  the  sheets 
were  broken,  lapped  1^  to  3 in.  at  the  studs,  and  were  held  to- 
gether by  the  staples.  The  edges  of  the  sheets  at  the  hori- 
zontal joints  were  tied  together  between  each  stud  by  No.  18- 
gauge  tie  wire. 

The  observations  show  that  the  lath  can  be  properly  cut, 
handled,  fitted  and  attached  to  walls  and  partitions  on  the  in- 
terior of  buildings  having  wood  furring  and  studding  spaced  16 
in.  center  to  center,  in  the  manner  specified.  The  lath  can  be 
fitted,  placed  in  proper  position  and  attached  without  difficulty 
by  workmen  of  ordinary  experience,  but  care  must  be  exercised 
in  driving  the  staples  into  the  supports.  Nearly  50  percent  of 
the  staples  were  bent  over  and  imperfectly  driven  in  attaching 
the  lath  in  these  tests,  suggesting  the  use  of  a heavier  staple. 
With  this  exception  the  job  probably  represented  good  average 
work  in  all  essential  particulars.  The  lath  was  free  from  ex- 
cessive bulging  at  any  point  and  was  fairly  rigid  but  could  be 
bent  inward  between  the  studs  to  some  extent  under  the  pres- 
sure of  the  hand.  Only  the  ordinary  staging  and  tools  were  re- 
quired for  the  installation  of  the  lath. 

Preparation  and  Application  of  Plasters — The  plasters  were 
delivered  in  bags  and  the  sand  in  bulk,  and  were  stored  in  a 
clean,  dry  place  until  used. 

The  plaster  of  the  scratch  coat  was  prepared  in  an  ordinary 
.nixing  box,  one  end  of  which  was  slightly  higher  than  the  other. 
A layer  of  sand  was  placed  in  the  box  and  then  an  equal  volume 
of  extra  fibered  gypsum  plaster,  this  proportion  being  close  to 
100  lbs.  of  plaster  to  150  lbs.  of  sand.  The  plaster  and  sand 
were  then  hoed  from  one  end  of  the  box  to  the  other,  until  the 
dry  mixture  was  uniform  in  color.  Clean  water  was  then 
placed  in  the  lower  end  of  the  box  and  the  dry  mixture  hoed 
into  it  until  the  plaster  was  uniformly  mixed  to  the  proper  con- 
sistency for  application. 

The  plaster  for  the  brown  coat  was  prepared  in  the  same 
way,  one  part  of  regular  fibered  gypsum  plaster  being  used  to 


10 


INSTALLATION  TESTS 


two  parts  of  sand  by  volume,  this  preparation  being  close  to 
100  lbs.  of  plaster  to  300  lbs.  of  sand. 

The  lime  putty  finish  coat  of  plaster  was  prepared  by  form- 
ing a ring  of  lime  putty  about  6 in.  high  on  a mortar  board, 
placing  about  4 in.  of  water  in  the  ring,  sifting  the  dry  gypsum 
plaster  into  the  water,  and  thoroughly  mixing  with  the  lime 
putty  after  the  gypsum  plaster  had  soaked  for  several  minutes 
and  had  been  mixed  to  a creamy  consistency.  One  part  of  gyp- 
sum plaster  was  mixed  with  about  three  parts  of  lime  putty  by 
volume.  The  finish  coat  was  mixed  to  a uniform  paste  ready 
for  application. 

A thin  coat  of  plaster  was  first  applied  to  the  lath  on  both 
sides  of  each  of  the  panels.  The  plaster  was  applied  lightly  but 
with  sufficient  pressure  to  force  it  well  through  the  mesh,  imbed 
the  metal  and  form  full  keys.  Sufficient  plaster  was  applied  to 
thoroughly  cover  the  lath  on  the  plaster  side.  After  the  coat 
had  set  for  a few  minutes,  the  surface  was  thoroughly  scratched 
in  both  directions  with  the  edge  of  a piece  of  the  metal  lath. 

After  the  scratch  coat  had  dried  for  about  18  hours,  the 
brown  coat  was  applied.  Sufficient  plaster  was  spread  on  to 
bring  the  coating  out  nearly  flush  with  the  grounds  and  the 
surfaces  then  made  straight  and  true  with  a rod  and  darby  but 
were  left  rough  under  the  tools  to  furnish  a bond  for  the  finish 
coat. 

After  the  brown  coat  had  dried  for  about  five  days,  the  lime 
putty  finish  coat  was  applied.  The  surface  of  the  brown  coat 
was  first  sprinkled  slightly  with  clear  water  and  a thin  coat  of 
the  plaster  then  thoroughly  troweled  on,  applying  enough  plas- 
ter to  cover  the  brown  coat  completely.  Enough  additional 
plaster  was  then  applied  to  make  the  wall  straight  and  true. 
The  surfaces  were  then  gone  over  again  with  the  material  as 
thin  as  it  could  be  handled  and  all  imperfections  worked  out 
and  the  coating  troweled  to  a smooth,  uniform  surface. 

The  observations  show  that  when  ordinary  facilities  are  pro- 
vided, these  plasters  can  be  properly  handled  and  mixed  by 
workmen  reasonably  familiar  with  this  class  of  work.  The  mix- 
ing box  must  be  tight  and  of  ample  size  for  the  batches  used. 
The  workmen  must  understand  the  importance  of  obtaining  the 
proper  proportions,  of  prompt  completion  of  the  batch  mixes, 
and  of  clean  tools.  The  use  of  mixed  plaster  that  has  com- 
menced to  set  must  be  avoided. 

Application  of  Spot  Grounds  and  Finish — After  the  scratch 
coats  had  become  dry  a row  of  spot  grounds  was  installed  at 
the  points  where  the  base  boards,  chair  rails  and  picture  mould- 
ings were  to  be  attached.  A layer  of  special  gypsum  plaster 


11 


WALLS  AND  PARTITIONS 


was  spread  on  the  scratch  coats  at  the  points  where  the  grounds 
were  to  be  located  and  the  grounds  at  each  end  of  each  row 
pressed  firmly  into  the  gypsum  until  the  outer  faces  of  the 
grounds  were  ^ in.  from  the  supports.  Lines  were  then 
stretched  between  these  grounds  and  the  intermediate  grounds 
set  so  that  their  outer  faces  were  flush  with  the  line.  Rows  of 
6 or  7 grounds  were  employed  at  the  chair  rails  and  picture 
moulding,  and  rows  of  8 at  the  base  boards.  The  spacing  be- 
tween the  grounds  varied  from  143^  to  in. 

The  observations  show  that  the  spot  grounds  can  be  prop- 
erly installed  by  workmen  who  are  familiar  with  the  instruc- 
tions and  who  have  had  some  experience  in  handling  the  gyp- 
sum plaster  used  in  setting  and  in  securing  alignment.  All  of 
the  spot  grounds  used  were  securely  attached,  located  in  a 
straight  line,  and  fairly  true  in  respect  to  their  outer  surfaces. 
They  were  installed  by  an  experienced  man  but  the  observa- 
tions indicated  that  the  work  could  be  accomplished  by  work- 
men of  ordinary  experience. 

Baseboards,  chair  rails  and  picture  mouldings  were  attached 
to  each  side  of  each  pane.  The  baseboards  were  located  at  the 
bottom  of  the  panels,  the  chair  rails  36  in.  above  the  bottom 
and  the  picture  moulding  12  in.  from  the  top  of  the  panels. 
These  members  were  attached  by  one  or  two  long  wire  nails 
driven  through  the  trim  into  each  spot  ground  two  nails  being 
used  in  most  cases.  The  trim  was  drawn  close  to  the  plaster 
surface  in  all  cases  and  all  grounds  remained  firm  and  secure, 
without  injury  to  the  plaster. 

The  observations  show  that  wood  trim  can  be  securely  at- 
tached to  the  spot  grounds  used  and  that  the  trim  can  be  made 
to  fit  closely  to  the  finish  if  reasonable  care  is  taken  to  obtain 
proper  alignment  of  the  grounds  and  true  plaster  surfaces  be- 
tween the  grounds. 

Maintenance — The  observations  during  the  construction  of 
the  panels  indicate  that  the  materials  are  of  such  a form  and  so 
arranged  that  injured  portions  of  the  finish  can  be  readily  re- 
paired or  removed  and  replaced.  The  damaged  plaster  can  be 
removed  and  replaced  by  new  plaster  and  finished  off  flush  with 
the  uninjured  plaster  surfaces.  In  case  of  injuries,  sufficiently 
extensive  to  rupture  both  the  lath  and  the  plaster,  new  lath  can 
be  attached  to  the  old  or  extended  back  and  attached  to  the 
supports  and  replastered.  The  staples  and  nails  in  the  lath  can 
be  pulled  out  or  new  staples  or  nails  installed  in  replacing  the 
lath.  The  gypsum  plasters  will  bond  with  the  old  and  provide 
tight  joints  at  the  junctions  thus  formed. 


12 


INSTALLATION  TESTS 


Durability  and  Strength — The  observations  during  the  con- 
struction of  the  panels  showed  that  the  lath  can  be  securely  at- 
tached to  wood  supports  and  that  the  plaster  can  be  well  keyed 
and  bonded  to  the  lath  and  that  the  finish  becomes  very  hard 
and  stiff  after  the  plaster  has  dried  out.  The  observations  indi- 
cate that  the  lath  serves  to  reinforce  the  plaster  coatings  in  all 
directions  to  such  an  extent  that  the  finish  should  be  capable  of 
resisting  all  ordinary  stresses  and  deteriorating  influences  except 
excessive  moisture  and  repeated  or  continued  high  temperatures. 

Uniformity — The  observations  indicate  that  in  the  hands  of 
workmen  of  ordinary  ability,  this  construction  can  be  installed 
in  a uniform  and  secure  manner  under  the  conditions  usually 
found  in  practice. 


13 


FIRE  ENDURANCE  TEST  No.  1: 

This  test  was  made  as  prescribed  in  the  “Standard  Specifica- 
tions for  Fire  Tests  of  Materials  and  Construction'^  for  a non- 
bearing partition. 

DESCRIPTION  OF  TEST  PANEL 

One  of  the  panels  built  as  described  for  the  Installation  Test 
was  employed  in  this  test.  It  consisted  of  a wood  stud  frame 
covered  on  both  sides  with  the  metal  lath  and  gypsum  plaster 
finish  under  investigation.  It  was  10  ft.  wide  and  11  ft.  high 
in  the  opening  in  the  wall,  and  approximately  5j4  in.  in  thick- 
ness. The  face  of  the  panel  exposed  to  the  fire  was  about  7}4 
in.  back  from  the  face  of  the  brick  wall  at  one  edge  and  about 
6^  in.  at  the  other.  The  panel  was  29  days  old  when  tested 
and  had  been  allowed  to  season  in  freely  circulating  air  inside  a 
building  at  temperatures  well  above  the  freezing  point.  The 
panel  was  firm  and  sound  and  apparently  in  a normally  dry 
condition. 

The  finish  on  each  face  of  the  panel  consisted  of  24-in.  sheets 
of  No.  26  U.  S.  gauge  lath  of  the  expanded  metal  type  and  the 
diamond  mesh  pattern  applied  in  horizontal  courses,  a 
scratch  coat  of  extra  fibered  gypsum  plaster,  a brown  coat  of  reg- 
ular fibered  gypsum  plaster  and  a finish  coat  of  lime  putty  tem- 
pered with  gypsum  plaster  applied  as  advocated.  At  the  bor- 
ders of  the  panels  both  lath  and  plaster  were  turned  at  right 
angles  and  flanged  2 to  6 in.  against  the  masonry  forming  the 
boundaries  of  the  opening  in  the  test  wall.  On  the  fire  side  the 
thickness  of  the  finish,  as  measured  at  24  points,  varied  from 

in.  to  -Jf  in.,  the  average  thickness  being  approximately  ^ in. 
On  the  unexposed  side  the  thickness  of  the  plaster  varied  from 
% in.  to  J4.  in.,  the  average  thickness  being  approximately  in. 
The  plastered  surfaces  were  hard  and  without  cracks  or  other 
visible  defects.  The  surfaces  were  smooth  and  true,  so  far  as 
indicated  by  visual  observation.  There  were  no  cracks  at  the 
joints  between  the  panel  and  the  enclosing  masonry.  The  wood 
trim  was  in  close  contact  with  the  plastered  surfaces  and  se- 
curely attached  to  the  spot  grounds. 

The  appearance  of  the  panel  before  the  test  is  shown  by  Fig- 
ures 1 and  2. 


TEST  METHOD 

The  standard  test  equipment  described  in  Appendix  V was 
used  in  the  test. 

The  movable  wall  carrying  the  panel  was  drawn  in  front  of 
the  furnace,  the  end  wall  closed,  the  apparatus  for  measuring 
furnace  pressures,  deflections  and  temperatures  installed  and 
the  fire  started.  The  inner  face  of  the  panel  was  exposed  to 


14 


FIRE  ENDURANCE  TEST  No.  1 


the  standard  fire  conditions  in  which  the  temperature  rises  rap- 
idly to  approximately  1500  degrees  Fahr.  during  the  first  30 
minutes,  to  approximately  1700  degrees  Fahr.  at  the  end  of  one 
hour  and  then  gradually  upward  until  the  end  of  the  test.  (See 
Fig.  6.)  The  test  was  continued  until  the  panel  failed  by  the 
passage  of  fire  through  it,  after  which  the  fire  in  the  furnace 
was  extinguished  and  the  panel  was  immediately  drawn  away 
from  the  furnace  and  sprayed  with  water  until  the  fire  in  the 
burning  parts  was  extinguished. 

Observations  were  made  throughout  the  test  covering  the 
distribution  and  general  character  of  the  fire,  the  color  of  the 
panel  due  to  heat,  and  the  pressures  and  temperatures  in  the 
furnace. 

Observations  were  made  during  and  after  the  test  covering 
the  flame  and  heat  resisting  properties  of  the  panel,  develop- 
ments such  as  are  detailed  in  the  following  paragraphs  and  hav- 
ing a bearing  on  either  of  these  features  being  noted  and  re- 
corded. ' 

Flame  Resistance — As  indicated  by  the  passage  of  smoke  or 
flame  into,  through  or  around  the  panel  due  to  the  development 
of  separations  by  cracking,  spalling,  splitting,  bulging,  or  dis- 
lodgement  of  the  parts,  and  as  indicated  by  the  stability  of  the 
panel  during  and  after  the  test. 

Heat  Resistance— As  indicated  by  any  apparent  insulating 
effect  on  the  wood  studs  afforded  by  the  exposed  finish,  the  con- 
dition of  the  materials  during  and  after  the  test,  the  tempera- 
tures at  points  on  the  unexposed  face  of  the  panel,  and  the  sta- 
bility of  the  panel  during  and  after  the  test. 

Record  was  made  during  the  test  of  the  bulging  or  other  * 
distortion  of  the  face  of  the  panel  not  exposed  to  the  fire.  Thir- 
teen targets  were  mounted  on  the  panel  as  shown  in  Fig.  2,  and 
readings  were  taken  at  5-min.  intervals  of  their  movement  by 
means  of  a transit  telescope. 

The  results  of  the  test  were  studied  to  determine  the  degree 
of  fire  protection  furnished  by  the  partitions,  taking  into  ac- 
count their  design  and  construction  and  the  fire  exposure  to 
which  they  are  likely  to  be  subjected  in ‘the  situations  and  in 
the  classes  of  buildings  for  which  they  are  advocated. 

RESULTS 

The  following  is  a summarization  of  the  results  observed 
during  and  after  the  test,  the  developments  relating  to  each 
feature  mentioned  above  and  the  conclusions  drawn  therefrom 
being  given  under  their  respective  headings. 

The  appearance  of  the  panel  before  and  after  the  test  is 
shown  by  Figs.  1 to  5 inclusive.  The  average  indicated  tem- 


15 


WALLS  AND  PARTITIONS 


peratures  in  the  furnace  and  on  the  unexposed  face  of  the  panel 
are  shown  by  the  curves  of  Fig.  6. 

Character  of  Fire — The  distribution  of  the  fire  was  rather  un- 
even for  the  first  15  minutes,  the  minimum  exposure  being  in  the 
south  upper  portion.  After  15  minutes,  the  fire  was  well  dis- 
tributed. Impinging  of  jets  of  flame  against  the  face  of  the 
panel  was  observed  at  the  south  portion  from  70  minutes  to  100 
minutes  after  the  start,  no  impinging  occurring  at  other  times. 
The  fire  was  practically  non-luminous  for  the  first  hour  and 
slightly  luminous  during  the  second  and  the  third  hours.  The 
panel  showed  a trace  of  color  at  5 minutes  and  was  full  red  at 
20  minutes.  In  28  minutes  the  color  was  bright  red  in  the  south 
central  portion  and  from  about  45  minutes  until  the  end  of  the 
test,  the  panel  was  fairly  uniformly  a bright  red.  The  pressure 
in  the  furnace  was  slightly  above  atmospheric  throughout  the 
test.  The  average  furnace  temperatures  were  slightly  higher 
than  the  standard  temperatures  and  are  shown  by  the  time-tem- 
perature curve  in  Fig.  6. 

Flame  Resistance — On  the  face  of  the  panel  exposed  to  the 
fire  the  wood  baseboard,  chair  rail  and  picture  moulding  began 
to  char  and  burn  almost  immediately  and  were  practically 
consumed  at  25  min.  The  wood  portions  of  the  spot  grounds 
were  consumed  as  the  test  progressed,  leaving  holes  through 
the  brown  and  finish  coats  down  to  plaster  used  to  attach  the 
grounds.  See  Fig.  3.  The  metal  bases  of  the  spot  grounds  re- 
mained in  position  throughout  the  test  and  no  openings  were 
formed  through  the  finish  or  splitting  or  cracking  of  the  plaster 
was  caused  by  the  spot  grounds. 

At  20  min.,  a small  vertical  crack  was  noticeable  in  the  plas- 
ter on  the  north  side  above  the  chair  rail.  At  35  min.  another 
small  crack  developed  south  of  the  middle  of  the  panel  and  below 
the  chair  rail.  The  length  and  width  of  these  cracks  gradually 
increased  as  the  test  progressed,  the  increases  in  width  being 
caused  by  the  bulging  of  the  brown  and  finish  coats  on  each 
side  of  the  cracks. 

At  1 hr.  and  50  min.  a third  crack  developed  south  of  the 
middle,  and  several  other  cracks  occurred  later  in  the  test,  but 
these  did  not  open  up  to  any  great  extent.  The  first  and  second 
cracks  at  80  min.  appeared  about  1 in.  and  ^-in.  wide  respect- 
ively, and  at  the  end  of  the  test  2 in.  and  1 in.  wide,  respectively, 
at  the  middle,  the  first  crack  extending  nearly  the  full  length 
of  the  panel.  The  scratch  coat  apparently  was  intact.  The  fact 
that  very  little  gas  from  the  burning  studs  entered  the  furnace 
during  the  test  also  indicates  that  the  scratch  coat  remained 
fairly  tight,  although  the  character  of  the  fire  after  one  houi 
showed  the  escape  of  some  gas  through  the  finish.  Examination 


16 


FIRE  ENDURANCE  TEST  No.  1 


after  the  test  showed  the  scratch  coat  in  position  on  the  lath 
and  that  it  was  considerably  cracked  and  otherwise  injured  by 
local  buckling  in  the  lath. 

At  30  min.  the  plaster  was  bulged  slightly  away  from  the 
fire  at  the  middle  of  the  panel.  This  bulging  gradually  in- 
creased in  area  and  extent  as  the  test  progressed  until  at  3 
hours  it  had  extended  over  an  area  about  4 ft.  wide  and  6 ft. 
long  and  was  apparently  away  from  the  fire  at  the  middle  of  the 
panel.  The  plaster  was  apparently  completely  calcined  but  did 
not  fall  at  any  point  during  the  test  and  no  openings  developed 
that  would  permit  the  passage  of  flame  through  the  finish.  The 
strength  of  the  plaster  was  mostly  destroyed.  The  brown  and 
finish  coats  were  insecure  and  portions  fell  from  position  when 
the  panel  was  drawn  from  the  furnace  and  sprayed  by  a ^-in 
nozzle  at  the  end  of  the  test.  The  appearance  of  the  panel  at 
3 hours  is  shown  by  Fig.  3.  The  studs  were  almost  entirely 
consumed  and  afforded  no  support  for  the  finish.  The  remain- 
ing fragments  of  the  studs  were  glowing  freely.  All  of  the 
finish  on  the  fire  side  of  the  panel  was  very  insecure  and  it 
fell  from  position  about  an  hour  after  the  panel  was  withdrawn 
from  the  furnace  when  one  of  the  lower  corners  was  slightly 
disturbed  by  a small  pinch  bar  inserted  between  the  brickwork 
and  the  flanged  edge.  The  appearance  of  the  panel  after  the 
collapse  is  shown  by  Fig.  4. 

On  the  unexposed  face  of  the  panel,  steam  appeared  at  15 
min.,  at  some  points  at  the  edges,  becoming  less  in  volume  at 
30  min.  and  practically  ceasing  at  55  min.,  when  smoke  began 
to  appear  at  some  points  at  the  edges.  At  65  min.  slight  smoke 
passage  developed  at  a crack  near  the  middle  of  the  panel  and 
at  other  cracks  in  this  locality  at  100  min.,  the  finish  being  con- 
siderably cracked  down  through  the  middle  of  the  panel  at  this 
and  later  periods.  Smoke  issued  at  other  cracks  and  increased 
in  volume  as  the  test  progressed.  At  2 hr.  and  50  min.  smoke 
developed  at  the  chair  rail  and  picture  moulding  and  small 
flames  developed  near  the  north  and  south  ends  of  the  chair 
rail  9 and  10  min.  later,  respectively,  being  apparently  caused 
by  the  transmission  of  heat  rather  than  the  passage  of  flame 
through  the  panel.  The  panel  was  removed  from  the  furnace  at 
3 hr.,  134  min.,  at  which  time  the  wood  studs  had  been  largely 
destroyed  and  were  burning  briskly.  The  condition  of  the  un- 
exposed face  of  the  panel  after  the  test  is  shown  by  Fig.  5,  the 
photograph  having  been  taken  after  the  chair  rail  was  almost 
totally  consumed. 

These  observations  indicate  that  when  in  good  condition  and 
exposed  to  fire  that  has  passed  the  incident  stage  and  involves 
freely  burning  material  in  the  interior  of  a building,  this  con- 


17 


WALLS  AND  PARTITIONS 


struction  will  serve  as  an  effective  barrier  to  the  passage  of 
flame  into  opposite  areas  for  periods  in  excess  of  one  hour. 
Under  most  conditions  the  finish  will  serve  to  prevent  such 
flame  passage  until  the  attachments  fail  and  collapse  takes 
place.  Fire  will  be  transmitted  by  conduction  to  the  wood  sup- 
ports and  other  combustible  material  in  hollow  spaces  of  the 
construction  before  the  finish  fails  by  the  formation  of  openings. 

Heat  Resistance — The  degree  of  heat  insulation  afforded  by 
the  finish  was  not  clearly  apparent  from  the  observations  made 
on  the  face  of  the  panel  exposed  to  fire,  but  it  was  practically 
certain  that  fire  reached  the  studs  by  the  heat  transmitted 
through  the  finish  by  conduction  or  through  small  cracks  caused 
by  buckling  or  expansion.  Separations  in  the  outer  two  plaster 
coatings  occurred  at  20  min.  and  at  later  stages  the  openings 
in  these  coatings  were  sufficiently  large  at  two  points  to  permit 
the  heat  and  flame  to  reach  the  scratch  coat  directly.  The  plaster 
coatings  possessed  sufficient  strength  and  adhesion  to  remain 
in  position  through  the  entire  test,  rendering  it  impossible  to 
observe  when  the  studs  took  fire.  The  condition  of  the  fire  in 
the  furnace  at  1 hr.  15  min.  showed  that  gases  from  the  wood 
studs  were  escaping  into  the  furnace,  indicating  that  the  wood 
had  been  burning  for  some  time  previously.  At  the  end  of  the 
test  the  plaster  coatings  appeared  to  be  thoroughly  calcined, 
and  the  scratch  coat  was  sufficiently  cracked  at  the  separations 
in  the  outer  plaster  coats  to  permit  greater  transmission  of  heat 
but  not  passage  of  flame. 

On  the  unexposed  face  of  the  panel,  steam  was  noticeable 
during  the  first  55  min.,  after  which  smoke  developed  and  issued 
in  increasing  volume  at  the  edges  and  at  the  cracks  for  the  re- 
mainder of  the  test.  Hair  cracks  developed  in  the  plaster  each 
side  of  the  middle  at  5 min.  At  65  min.  a long  vertical  crack 
north  of  the  middle  increased  in  width  and  the  smoke  from  this 
crack  became  more  dense,  indicating  that  the  studs  were  burn- 
ing. At  1 hr.  40  min.,  the  cracks  north  of  the  middle  were  more 
marked  and  the  condition  of  the  finish  indicated  considerable 
heat  on  the  back  side.  From  this  time  on  the  cracks  in  all 
parts  became  more  pronounced  and  indicated  severe  fire  on  the 
inside  of  the  panel. 

The  highest  recorded  temperature  for  the  unexposed  face 
was  246  deg.  Fahrenheit  at  2 hr.  and  10  min.,  at  which  time 
the  thermometers  were  removed.  The  maximum’  average  tem- 
perature indicated  by  the  five  thermometers  on  the  unexposed 
side  was  230  deg.  It  is  probable  that  the  temperatures  at  the 
points  where  flames  first  appeared  may  have  been  higher  at  2 
hr.  and  10  min.  than  the  temperatures  at  the  points  where  ther- 
mometers were  mounted.  The  wooden  chair  rail  ignited  at 


18 


FIRE  ENDURANCE  TEST  No.  1 


2 hr.  and  59  min.  at  a point  where  no  cracks  in  the  finish  on 
the  unexposed  face  were  observed,  indicating  that  the  tempera- 
ture of  ignition  of  wood  had  been  reached  by  direct  conduction 
through  the  plastering  on  the  unexposed  face. 

The  observations  indicate  that  when  in  good  condition  and 
exposed  to  fire  that  has  passed  the  incident  stage  and  involves 
freely  burning  material  on  the  interior  of  a building,  the  heat 
insulating  property  of  the  finish  is  sufficient  to  prevent  the 
transmission  of  fire  to  the  wood  supports  back  of  it  for  about 
45  min.,  and  that  the  passage  of  fire  to  the  opposite  area  will 
occur  by  the  transmission  of  heat  through  the  construction  by 
conduction  before  openings  are  formed  that  will  permit  the 
passage  of  flame. 

. The  bulging  or  distortion  readings  taken  during  the  test  are 
shown  in  the  following  table  for.  the  15,  30,  45,  60,  120  and  180 
minute  periods.  The  targets  were  numbered  consecutively  from 
1 to  13  beginning  in  the  upper  south  corner  of  the  panel.  Hence 
the  readings  of  targets  Nos.  1,  2 and  3 show  movement,  if  any, 
at  the  top  edge  of  the  panel  and  similarly  targets  Nos.  11,  12 
and  13  are  for  the  bottom  edge.  Nos.  1,  5 and  11  for  the  south 
edge.  Nos.  3,  9 and  13  for  the  north  edge.  Nos.  2,  4,  7,  10  and 
12  for  the  vertical  center  line  and  Nos.  5,  6,  7,  8,  and  9 for  the 
horizontal  center  line.  Positive  readings  indicate  movement  of 
targets  away  from  the  original  plane  to  the  east  or  from  the 
fire. 

TABLE  OF  DEFLECTIONS 
Target  Numbers 


Time  of 


reading 
minutes  1 

2 

3 

4 

5 

6 

7 

8 

9 

10 

11 

12 

13 

Deflections 

; in  ( 

decimals  of 

inches. 

15 

.0 

.05 

.0 

.125 

.0 

*.075 

.15 

.05 

.025 

.10 

*.025 

.0 

.025 

30 

.075 

.05 

.05 

.20 

.0 

*.10 

.30 

0.15 

.050 

.20 

*.025 

.05 

:025 

45 

.075 

.025 

.10 

.30 

*.05 

*.175 

.40 

.25 

.025 

.30 

*.05 

.05 

.025 

60 

.075 

.05 

.10 

.45 

*.10 

*.125 

.60 

3.75 

.025 

.450*.05 

.05 

.0 

120 

.05 

.150 

1.60 

*.30 

*.25 

1.85 

.85 

*.050 

1 55 

*.15 

.05 

*.10 

180 

*.05 

.250 

;6‘ 

3.35 

.0 

.0 

3.25 

1.65 

.050 

3.35 

.0 

.10 

.05 

*denotes  deflection  toward  the  fire. 


The  deflections  show  practically  no  movements  at  the  edges 
of  the  panel  during  the  entire  3-hr.  period.  The  bulging  at  the 
vertical  and  horizontal  center  lines  indicates  plainly  the  lamina- 
tion crack  between  the  brown  and  scratch  coats  which  is  clearly 
shown  in  the  photograph,  Fig.  5.  A similar  lamination  or  sep- 
aration between  plaster  and  coatings  occurred  on  the  face  of  the 
panel  exposed  to  the  fire  as  shown  in  the  photograph.  Fig.  3. 

The  results  of  this  test  show  that  practically  no  distortion 
of  the  wood  frame  occurred  and  that  the  metal  lath  with  the 
scratch  coat  of  plaster  remained  in  close  contact  with  the  wood 
studs  until  these  studs  were  burned  away. 


19 


Figure  1 

View  before  test  of  exposed  face  of  sample  used  in  Fire  Endurance 

Test  No.  1 


20 


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\n 

FIRE  ENDURANCE  TEST  NO  2: 

DESCRIPTION  OF  SAMPLE 

The  sample  used  in  this  test  was  like  the  sample  used  in 
Fire  Endurance  Test  No.  1,  except  that  No.  27  U.  S.  gauge  ex- 
panded metal  lath  weighing  2.3  lbs.  per  sq.  yard  was  used  and 
attached  to  the  studs  by  lF2-in.  common  wire  nails  driven  into 
the  studs  and  bent  over  the  lath  spaced  about  6 in.  centers. 
Hair  fibered  gypsum  plaster  was  mixed  'with  lake  sand  and  ap- 
plied as  described  for  the  hrst  sample. 

The  appearance  of  the  sample  during  and  after  installation 
is  shown  in  Figs.  7 to  9 inclusive. 

The  sample  was  about  10  ft.  wide  and  11  ft.  high  and  about 
5^4  in.  in  thickness;  was  about  in.  back  from  th  exposed 
face  of  the  brick  panel.  The  sample  was  30  days  old  when 


23 


wai!ls  and  partitions 


tested  and  had  been  seasoned  under  conditions  similar  to  those 
of  the  sample  used  for  Fire  Endurance  Test  No.  1.  No  cracks 
or  separations  were  apparent  in  the  sample  before  test.  The 
thickness  of  the  finish  as  measured  on  the  unexposed  face  at  16 
points  average  in.  over  supports. 

Appearance  of  the  sample  before  test  is  shown  by  Fig.  8 
and  9. 

Object  of  Test — The  object  of  the  test  was  to  determine  the 
condition  of  the  wood  supports  at  the  expiration  of  the  test  pe- 
riod for  a one-hour  classification,  accordingly  the  test  was  con- 
tinued for  one  hour  and  fifteen  min.,  the  required  test  period. 
(80  per  cent  of  75  min.  equals  60  min.,  one  hr.) 

TEST  METHODS 

The  standard  test  equipment  described  in  Appendix  V.  was 
used  in  this  test. 

The  test  methods  employed  were  like  those  of  Fire  Endurance 
Test  No.  1,  except  that  the  test  was  continued  for  75  min.,  when 
the  furnace  fire  was  extinguished  and  the  sample  withdrawn 
from  the  furnace  and  that  a l^^-in.  hose  stream  was  applied  to 
the  exposed  face  for  1 min.,  the  pressure  being  30  lbs.  per  sq.  in. 
and  the  nozzle  20  ft.  from  the  sample.  The  stream  was  directed 
first  slowly  around  the  edges  and  then  over  the  entire  sample. 

The  hose  stream  was  applied  to  extinguish  any  flame  in  the 
hollow  spaces  of  the  sample  and  thus  permit  ascertaining  the 
exact  condition  of  the  wood  supports  at  75  min.,  1^  times  the 
period  for  which  a rating  was  desired. 

Ten  thermocouples  were  inserted  through  unexposed  face 
of  the  sample  into  the  hollow  spaces  between  studs.  The  couples 
were  symetrically  distributed  in  the  sample  and  were  so  ad- 
justed that  it  was  possible  to  take  the  temperatures  of  the 
hollow  spaces  and  also  the  temperatures  on  the  inner  face  of 
the  exposed  finish.  The  location  of  the  thermocouples  is  shown 
by  Fig.  9. 


RESULTS 

The  following  results  were  observed  during  and  after  the 
test. 

The  appearance  of  the  sample  after  test  is  shown  by  Figs. 
10  to  15  inclusive. 

The  furnace,  interior  and  unexposed  temperatures  of  the 
sample  are  shown  by  Fig.  16. 

Character  of  Fire — The  fire  was  semi-luminous  during  the 


24 


FIRE  ENDURANCE  TEST  No.  2 


first  15  min.  and  had  a tendency  to  swerve  from  the  north 
to  south  side  of  the  sample  during  the  first  10  min.,  becoming 
more  evenly  distributed  at  15  min.  and  remaining  well  dis- 
tributed and  luminous  during  the  remainder  of  the  test. 

The  sample  showed  signs  of  color  in  small  areas  at  15  min., 
was  dark  red  at  25  min.,  and  glowing  at  30  min.,  the  color 
increased  in  intensity  during  the  remainder  of  the  test  and  was 
a bright  red  over  the  entire  area  when  the  sample  was  removed 
from  the  furnace. 

The  average  furnace  temperatures  were  slightly  below  the 
standard  curve  during  the  first  40  min.  and  followed  the  curve 
closely  during  the  remainder  of  the  test  period. 

Flame  Resistance  on  Exposed  Face — The  wood  trim  began 
to  char  and  burn  almost  immediately  and  was  nearly  all  con- 
sumed at  25  min.  The  wood  portion  of  the  spot  grounds  began 
to  burn  at  30  min.  and  were  practically  consumed  at  the  end  of 
the  test.  The  metal  base  of  the  spot  grounds  remained  in  posi- 
tion throughout  the  test  and  no  cracking  or  openings  through 
the  finish  were  formed  by  the  spot  grounds. 

At  53  min.  a small  vertical  crack  was  apparent  in  the  lower 
half  about  the  middle  of  the  sample  and  increased  slightly  in 
width,  extending  upward  as  the  test  progressed.  The  location 
and  size  of  crack  at  the  end  of  the  test  is  shown  by  Fig.  10 
No  other  cracks  were  apparent  during  or  at  the  end  of  the  test. 

At  30  min.  a slight  bulge  was  apparent  and  small  flakes  of 
the  finish  coat  fell.  No  marked  increase  in  the  bulging  was 
noted  during  the  remainder  of  the  test,  but  the  small  areas  of 
finish  coat  continued  to  fall  at  intervals  during  the  remainder 
of  the  period. 

The  condition  of  the  exposed  face  immediately  after  re- 
moval from  the  furnace  at  75  min.  and  before  the  water  stream 
was  applied  is  shown  by  Fig.  10.  Its  appearance  after  the 
hose  stream  was  applied  is  shown  by  Figs.  11  and  12. 

The  gypsum  plaster  finish  on  the  exposed  face  was  badly 
calcined  and  retained  very  little  of  its  original  strength.  The 
water  washed  away  the  greater  part  of  the  finish.  The  ex- 
panded metal  was  apparently  in  normal  condition,  but  was 
pulled  from  position  in  several  places,  due  to  the  water  stream 
and  the  wood  charring  around,  the  nails  which  were  easily 
pulled  from  position.  See  Figs.  12  and  14. 

The  studs  were  charred  on  the  side  next  to  the  exposed 
plaster  ranging  from  a mere  discoloration  to  i%-in.  near  the 
middle  of  the  sample. 


25 


WALLS  AND  PARTITIONS 


No  apparent  bulging  or  cracking  was  noted  in  the  studs. 

The  condition  of  a section  of  the  studding  from  the  ex- 
posed face  with  the  metal  lath  and  plaster  removed  is  shown  by 
Fig.  13. 

On  the  unexposed  face  of  the  panel,  steam  appeared  around 
the  thermocouple  openings  at  11  min.,  increasing  in  volume  until 
55  min.  and  showing  very  little  change  during  the  remainder 
of  the  period.  Smoke  mixed  with  the  steam  was  first  detected 
at  42  min.  and  increased  slightly  in  volume  as  the  test  prog- 
ressed. Damp  spots  appeared  on  the  unexposed  face  of  the 
panel  at  32  min.,  increasing  slightly  during  the  remainder  of 


Figure  7 

View  of  exposed  face  of  panel  used  in  Fire 
Endurance  Test  No.  2,  showing  finish  ap- 
plied on  exposed  face  and  also  location  of 
studs,  bridging  and  metal  lath  applied  on  the 
unexposed  face. 


26 


2 


Figure  8 * Figure  9 

View  of  exposed  face  of  panel  used  in  Fire  View  of  exposed  face  of  panel  used  in  Fire 

Endurance  Test  No.  2 before  test.  Endurance  Test  No.  2 before  fire  showing 

locations  of  thermocouples  for  measuring  in- 
terior temperatures  in  sample. 


Figure  10 

View  of  exposed  face  of  panel  used  in  Fire  Endurance  Test  No.  2 
when  removed  from  furnace  after  75  min.  standard  fire  exposure 
and  before  the  hose  stream  was  applied,  showing  the  vertical  cen- 
tral crack  and  standing  finish  consumed. 


28 


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29 


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30 


Figure  14 

View  showing  maximum  charring  in  2 by  4-in.  studs  after  exposure  to 
standard  fire  conditions  for  75  min.  Note  charring  at  nail  holes. 


31 


WALLS  AND  PARTITIONS 


the  test.  The  appearance  of  the  unexposed  face  of  the  sample 
after  the  hose  stream  was  applied  to  the  opposite  face  is  shown 
by  Fig.  15. 

The  gypsum  plaster  coating,  metal  lath  and  the  standing  fin- 
ish on  the  unexposed  face  were  apparently  undamaged  by  the 
fire. 

These  observations  warrant  conclusions  as  to  the  property  of 
resisting  passage  of  flame  similar  to  those  for  the  Fire  Endur- 
ance Test  No.  1. 

Heat  Resistance — The  extent  of  the  insulation  afforded  by 
the  finish  was  not  apparent  from  observations  it  was  possible 
to  make  from  the  fire  side  during  the  test. 


32 


FIRE  ENDURANCE  TEST  No.  2 


The  rise  of  temperatures  as  indicated  by  the  thermocouples 
installed  in  the  hollow  spaces  between  studs  and  in  contact 
with  the  back  of  the  exposed  face  of  the  sample  are  shown  by 
Fig.  16.  The  highest  temperature  recorded  on  the  back  face 
of  the  exposed  face  of  the  sample  was  630  deg.  F.  at  75  min. 
and  all  thermocouples  registered  over  500  deg.  F.  for  this  sur- 
face at  end  of  the  test. 

The  highest  temperature  recorded  on  the  unexposed  face 
of  the  sample  was  176  deg.  F.  at  75  min. 

The  maximum  and  minimum  temperatures  on  the  unexposed 
face  of  the  sample  are  shown  by  Fig.  16. 

Observations  indicate  that  when  this  finish  is  in  good  con- 
dition and  exposed  to  standard  fire  conditions  for  75  min.  and 
then  subjected  to  hose  stream  for  1 min.,  the  exposed  finish 
will  prevent  the  active  combustion  of  the  wood  suports  back 
of  it  for  about  45  min.,  after  which  period  it  will  continue  to 
prevent  the  passage  of  fire  through  the  finish  and  into  the  hol- 
low spaces  in  the  construction  for  at  least  one  hour.  Upon  ap- 
plication of  a hose  stream  immediately  following  the  fire  ex- 
posure, the  fire  resisting  properties  of  the  exposed  finish  will 
be  destroyed,  although  the  unexposed  face  of  the  partition  will 
retain  considerable  value  as  a fire  retardant,  and  the  strength 
of  the  bearing  members  will  not  be  materially  impaired  by  the 
charring  in.  max.)  noted  on  the  edges  of  the  studs  next  to 
the  exposed  finish. 

Bulging  and  distortion — No  marked  deflection  was  observed 
on  the  unexposed  face  of  the  sample  during  the  test  showing 
that  practically  no  distortion  of  the  wood  frame  occurred  and 
that  the  finish  and  attachments  remained  in  position  through- 
out the  test. 

The  appearance  of  the  unexposed  face  of  the  sample  after 
test  is  shown  by  Fig.  15. 


FIRE  AND  HOSE  STREAM  TEST; 

This  test  was  made  as  prescribed  in  the  Standard  “Specifi- 
cations for  Fire  Tests  of  Materials  and  Construction”  for  a non- 
bearing partition  or  wall. 

DESCRIPTION  OF  TEST  PANEL 

The  remaining  panel  built  as  described  in  the  Installation 
Test  was  employed  in  this  test,  its  construction  being  practically 
identical  with  that  of  the  panel  used  in  the  Fire  Endurance 
Test  No.  1.  The  finished  panel  was  10  ft.  wide  and  11  ft.  high 
in  the  wall  opening  and  approximately  5^4  in.  in  thickness.  The 
face  of  the  panel  exposed  to  the  fire  was  about  7^  in.  back 
from  the  face  of  the  brick  wall  at  one  edge  and  about  in. 
at  the  other.  The  panel  was  29  days  old  when  tested  and  had 
been  allowed  to  season  in  freely  circulating  air  inside  a build- 
ing at  temperatures  well  above  the  freezing  point.  The  panel 
was  firm  and  sound  and  apparently  in  a normally  dry  condi- 
tion. 

On  the  fire  side  the  thickness  of  the  finish  as  measured  at 
24  points  varied  from  16  to  1 in.  outside  the  studs,  the  average 
thickness  at  the  supports  being  approximately  %-in.  On  the 
unexposed  side  the  thickness  of  the  finish  varied  from  ^ to 
1^-in.  outside  the  studs,  the  average  thickness  at  the  supports 
being  approximately  it  in.  The  thickness  of  the  plaster  formed 
by  the  keys  on  the  back  of  the  lath  varied  from  ^ to  ^ in.  at 
the  joints  between  the  lath  to  approximately  ^ and  ^-in.  at 
other  points. 

The  plastered  surfaces  were  hard  and  without  cracks  or 
other  visible  defects.  The  surfaces  were  smooth  and  true. 
There  were  no  cracks  at  the  joints  between  the  panel  and  the 
enclosing  masonry.  The  wood  trim  was  in  close  contact  with 
the  plastered  surfaces  and  securely  attached  to  the  spot  grounds. 

The  appearance  of  the  panel  before  the  test  is  shown  by 
Figs.  17  and_18. 

FIRE  TEST: 

The  standard  test  equipment  described  in  Appendix  V was 
used  in  the  test.  '' 

METHOD 

The  methods  employed  and  observations  made  were  the 
same  as  in  the  Fire  Endurance  Test  No.  1 except  that  the  ap- 
paratus for  measuring  deflections  was  not  installed  on  the  un- 
exposed side,  and  that  the  fire  test  was  discontinued  at  45  min. 
when  the  panel  was  subjected  to  a fire  hose  stream  in  accord- 
ance with  the  standard  procedure  for  a one  hour  rating. 


34 


FIRE  AND  HOSE  STREAM  TEST 


RESULTS  OF  FIRE  TEST 

TEe  following  is  a summarization  of  the  results  observed 
during  and  after  the  fire  test,  the  developments  relating  to  each 
feature  and  the  conclusions  drawn  therefrom  being  given  under 
their  respective  headings. 

The  appearance  of  the  panel  before  and  after  the  test  is 
shown  by  Figs.  17  to  20  inclusive.  The  average  temperatures 
in  the  furnace  and  on  the  unexposed  face  of  the  panel  are  shown 
by  the  curves  of  Fig.  21. 

Character  of  Fire — The  distribution  of  the  fire  was  uneven 
for  the  first  10  min.,  the  maximum  exposure  being  in  the  north 
half.  The  distribution  was  corrected  slowly  and  was  fairly 
even  at  20  min.  and  until  the  end  of  the  test  period.  The  flames 
did  not  impinge  on  the  face  of  the  panel  to  any  considerable 
extent.  During  the  first  10  min.  the  fire  was  practically  non- 
luminous;  during  the  later  portions  of  the  test  it  was  luminous. 
The  panel  showed  some  color  at  10  min.  and  was  uniformly  fair- 
ly red  at  20  min.  The  pressure  in  the  furnace  was  slightly  above 
atmospheric  throughout  the  test.  The  average  furnace  tempera- 
tures were  slightly  higher  than  the  standard  temperatures 
and  are  shown  by  the  time-temperature  curve  in  Fig.  21. 

Flame  Resistance — On  the  face  of  the  panel  exposed  to  fire 

the  wood  trim  began  to  char  and  burn  almost  immediately  and 
was  practically  consumed  at  25  min.  The  wood  portions  of 
the  spot  grounds  were  consumed  later,  leaving  holes  through 
the  brown  and  finish  coats  down  to  the  plaster  used  to  attach 
the  grounds.  The  metal  bases  of  the  spot  grounds  remained 
in  position  throughout  the  test,  and  no  openings  through  the 
plaster  coating  nor  splitting  or  cracking  of  the  plaster  was 
caused  by  the  spot  grounds. 

At  13  and  18  min.  small  cracks  developed  in  the  north 
middle  portion  of  the  panel,  and  at  15  min.  two  diagonal  cracks 
occurred  in  the  same  locality,  but  these  cracks  did  not  open 
up  to  any  great  extent.  At  18  min.  a vertical  and  diagonal 
crack  occurred  on  the  north  side  near  the  middle  and  at  22 
min.  one  of  these  cracks  was  about  6 in.  long  and  j4-in.  wide, 
but  it  was  impossible  to  observe  whether  or  not  the  scratch 
coat  was  involved  or  if  the  separation  had  extended  through 
the  plaster  coating. 

The  fact  that  the  fire  did  not  show  evidence  of  any  appre- 
ciable escape  of  gas  from  the  wood  in  the  panel  during  the  test, 
nor  any  other  evidence  that  'the  studs  had  been  ignited,  seems 
to  show  that  no  openings  were  formed  that  would  permit  the 
passage  of  flame  through  the  plaster  coating. 


35 


WALLS  AND  PARTITIONS 


At  13  min.  a marked  bulge  was  noticeable  at  the  middle 
portion  of  the  panel.  This  increased  in  area  and  extended  some- 
what as  the  test  progressed,  but  the  plaster  did  not  fall  and 
it  was  impossible  to  observe  whether  the  entire  plaster  coat- 
ing was  involved  or  only  the  brown  and  finish  coats  of  plaster. 
The  furnace  fire  was  extinguished,  the  panel  withdrawn  from 
the  furnace  at  45  min.  and  the  standard  fire  hose  stream  applied 
about  Yz  min.  later.  Observation  during  this  test  indicated 
that  the  scratch  coat  was  intact  and  that  no  openings  had  been 
formed  through  the  plaster  coating  that  would  permit  the 
passage  of  flame. 

On  the  unexposed  face  of  the  panel  steam  issued  at  the  up- 
per edge  at  6 min.  and  smoke  at  8 min.  At  16  min.  steam  is- 
sued at  the  joint  between  the  panel  and  the  brickwork  on  the 
north  edge  and  at  25  min.  at  the  south  edge,  the  smoke  being 
still  confined  to  the  top  edge  of  the  panel.  The  volume  of  steam 
and  smoke  was  limited  at  all  times  during  the  test  and  did  not 
indicate  active  fire  within  the  panel.  The  wood  trim  was  not 
affected.  The  appearance  of  the  unexposed  face  of  the  panel 
after  the  Fire  and  Hose  Stream  Test  is  shown  by  Fig.  20. 

These  observations  warrant  conclusions  as  to  flame  retard- 
ant properties  agreeing  with  those  reached  for  the  Fire  En- 
durance Test  No.  1. 

Heat  Resistance — The  degree  of  heat  insulation  afforded  by 
the  construction  was  not  clearly  apparent  from  the  observa- 
tions on  the  exposed  face  of  the  panel  during  the  test.  Body 
cracks  were  noted  early  in  the  test  and  although  these  may  not 
have  extended  clear  through  the  plaster  coating,  they  undoubt- 
edly materially  reduced  its  insulating  properties.  The  plaster 
coats  retained  sufficient  strength  to  remain  in  place  throughout 
the  test  and  there  was  not  positive  evidence  at  the  end  of  the 
test  that  active  fire  had  been  communicated  to  the  studs.  Ex- 
amination after  the  Hose  Stream  Test  showed  that  the  edges 
of  some  of  the  studs  were  charred  in  places  to  a depth  of 
about  but  that  the  sides  of  the  studs  were  not  affected 

by  fire.  This  and  the  condition  of  the  charred  portions  seem 
to  show  that  no  flame  or  very  active  fire  had  taken  place,  al- 
though it  was  evident  that  at  the  charred  spots  the  wood  was 
very  close  to  its  ignition  point. 

The  highest  temperature  recorded  for  the  unexposed  face 
of  the  panel  was  174  deg.  Fahrenheit  at  the  end  of  the  test.  The 
maximum  average  temperature  readings  of  the  five  thermome- 
ters on  the  unexposed  face  was  164  deg.  The  average  tem- 
peratures on  unexposed  face  of  panel  are  shown  by  Fig.  21. 


36 


FIRE  AND  HOSE  STREAM  TEST 


Observations  indicate  that  when  in  good  condition  and  ex- 
posed to  standard  fire  conditions,  the  heat  insulating  property 
of  this  construction  is  such  as  to  delay  the  ignition  of  its 
wood  supports  for  about  45  min. 

APPLICATION  OF  HOSE  STREAM 

The  standard  test  equipment  described  in  Appendix  V was 
used  in  this  test. 

METHOD 

At  the  end  of  the  fire  test,  which  lasted  45  min.,  the  panel 
was  immediately  drawn  away  from  the  furnace  and  a 1^-in. 
fire  hose  stream  was  applied  from  a distance  of  20  ft.  for 
min.  The  stream  was  directed  first  at  the  center  of  the  panel, 
and  then  at  all  parts  of  the  exposed  face,  changes  in  the  direc- 
tion of  the  stream  being  made  slowly.  The  pressure  at  the 
base  of  the  nozzle  was  30  pounds  per  sq.  in.  throughout  the 
period. 

Observations  were  made  during  and  after  the  application 
of  the  stream  covering  the  effect  of'  the  impact  and  pressure 
and  the  rapid  cooling  on  the  flame  retarding  properties  of  the 
construction  as  indicated  by  openings  due  to  contraction, 
breakage,  dislodgements,  or  separations;  and  covering  the  ef- 
fect of  the  stream  on  the  heat  insulating  properties  of  the  panel, 
as  indicated  by  change  in  the  condition  of  the  material  or  re- 
duction in  the  thickness  of  the  plaster  coating  by  erosion  or 
dislodgement. 

The  results  of  the  test  were  studied  to  determine  the  gen- 
eral effect  of  the  application  of  hose  streams  on  the  fire  pro- 
tection furnished  by  the  construction. 

RESULTS  OF  HOSE  STREAM  TEST 

The  following  results  were  observed  during  the  test  and  the 
examinations  after  test,  the  developments  relating  to  each  fea- 
ture and  the  conclusions  drawn  therefrom  being  given  under 
their  respective  headings. 

The  appearance  of  the  panel  after  the  test  is  shown  by 
Figs.  19  and  20. 

Fire  Resistance — On  the  face  of  the  panel  exposed  to  the 
fire  and  to  the  hose  stream  the  flame  retarding  and  heat  in- 
sulating properties  of  the  plaster  coating  were  almost  imme- 
diately destroyed  when  the  stream  was  applied.  Most  of  the 
plaster  coating  was  dislodged  at  the  end  of  the  test  but  the 
lath  remained  securely  in  position.  The  outer  plaster  coat- 
ings were  badly  calcined  by  the  heat  and  did  not  possess  suf- 
ficient strength  to  resist  the  impact  and  eroding  effect  of  the 
stream.  They  were  thrown  off  in  fairly  large  pieces  under  the 
action  of  the  water,  the  dislodgements  immediately  following 


37 


WALLS  AND  PARTITIONS 


the  changes  in  direction  of  the  stream.  The  scratch  coat  also 
was  badly  calcined,  except  at  the  edges  and  in  the  lower  north 
corner,  and  was  mostly  dislodged  by  the  impact  and  eroding 
action  of  the  stream,  the  keys  being  broken  from  the  lath. 

These  results  show  that  the  fire  resistance  of  a single  finish 
is  destroyed  b}^  hose  streams  after  exposure  to  a standard 
fire  for  about  45  min.  and  indicate  that  this  would  be  the  case 
with  an  initial  fire  exposure  of  much  shorter  duration.  This 
is  due  to  the  fact  that  the  strength  of  the  gypsum  plaster  coat- 
ings is  destroyed  by  calcination. 

On  the  unexposed  face  of  the  panel  the  flame  retarding  and 
heat  insulating  properties  of  the  construction  were  practically 
unimpaired.  The  metal  lath  on  the  exposed  face  remained  in 
position  and  prevented  material  erosion  or  other  mechanical 
damage  from  the  hose  stream  to  the  plaster  coating  on  the  unex- 
posed side. 

These  results  show  that  a wood  stud  partition  or  wall  hav- 
ing the  described  metal  lath  and  gypsum  plaster  finish  on  two 
sides  retains  a very  considerable  value  as  a retardant  to  pass- 
age of  heat  and  flame  when  exposed  on  one  face  to  the  stand- 
ard fire  conditions  for  45  min.  and  to  the  impact  and  erosion 
of  a standard  hose  stream  and  indicate  that  this  would  be  the 
case  for  initial  fire  exposures  prior  to  application  of  hose  stream 
of  considerably  greater  duration. 


39 


Figure  17  Figure  18 

View  of  exposed  face  of  panel  used  in  Fire  View  of  unexposed  face  of  panel  used  in  Fire 

and  Hose  Stream  Test  before  test.  and  Hose  Stream  Test  before  test,  showing 

location  of  thermometers  mounted  on  face  of 
sample. 


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40 


SUPPLEMENTAL  FIRE  AND  HOSE  STREAM  TEST: 

This  test  was  made  to  develop  the  extent  of  damage  to 
the  finish  of  the  standard  hose  stream  applied  after  fire  ex- 
posures of  shorter  duration  than  in  the  Standard  Fire  En- 
durance Tests  and  the  Standard  Fire  and  Hose  Stream  Test. 

DESCRIPTION  OF  SAMPLES 

The  three  special  samples  employed  in  this  test  were  finished 
on  the  side  exposed  to  the  fire  with  a metal  lath  and  gypsum 
plaster  on  wood  frame  construction  similar  to  that  of  the 
samples  which  were  subjected  to  the  Standard  Fire  Endurance 
Test  No.  1 and  to  the  Fire  Hose  Stream  Test,  but  were  of 
reduced  dimensions  so  that  when  mounted  for  test  the  area 
exposed  to  the  fire  and  subsequently  to  the  hose  stream  was  in 
each  case  20  in.  wide  by  12  in.  high. 


41 


WALLS  AND  PARTITIONS 


METHOD 

Each  sample  was  separately  exposed  to  fire,  and  immediately 
thereafter  was  subjected  to  the  impact  eroding  and  cooling  ef- 
fects of  a hose  stream. 

The  tests  were  made  in  the  Underwriters’  Laboratories’ 
Furnace  No.  4,  which  for  the  purpose  of  this  test  was  pro- 
vided with  a rectangular  opening  20  in.  wide  and  12  in.  high 
in  the  brick  panel  forming  the  front  wall  of  the  furnace.  In 
each  test  the  sample  was  mounted  on  the  outer  face  of  the 
8-in.  front  wall,  so  as  to  be  exposed  to  the  fire  through  the 
rectangular  opening.  Exposure  to  fire  continued  for  30  min. 
in  Test  A,  for  15  min.  in  Test  B,  and  for  15  min.  in  Test  C. 
The  temperatures  within  the  furnace  were  indicated  by  means 
of  a Hoskins  thermocouple  mounted  opposite  the  center  of 
the  test  sample  and  8 in.  from  the  exposed  face. 

After  exposure  to  fire  for  the  assigned  period,  each  sample 
was  removed  from  the  furnace  and  subjected  to  the  action  of 
a hose  stream  from  a 1^-in.  smooth  nozzle,  20  ft.  from  the 
sample,  the  pressure  at  the  base  of  the  nozzle  being  30  pounds 
per  square  inch.  In  tests  A and  B the  hose  stream  was  ap- 
plied for  two  periods  of  2 seconds  each,  or  a total  of  4 seconds. 
In  Test  C the  application  of  the  stream  was  for  five  periods 
of  2 seconds  each,  or  a total  of  10  seconds.  Inasmuch  as  the 
exposed  area  of  each  sample  was  1%  sq.  ft.,  as  compared  with 
110  sq.  ft  in  the  sample  used  in  the  Standard  Hose  Stream  Test, 
a duration  of  2^  seconds  in  each  Supplementary  Hose  Stream 
Test  would  be  equivalent  to  the  2^  min.  of  the  standard  test. 

The  usual  observations  of'  the  condition  of  each  sample  were 
made  during  the  exposure  to  fire.  Detailed  observations  were 
made  after  the  application  of  the  hose  stream  in  order  to  de- 
termine whether  the  sample,  after  its  exposure  to  fire,  was  se- 
riously impaired  by  the  impact  and  erosion  of  the  stream. 

RESULTS 

The  temperatures  within  the  furnace  were  substantially  ac- 
cording to  the  Standard  Time-Temperature  Curve,  and  are 
stated  in  the  following  tabulation.  The  unusually  high  initial 
temperatures  in  Tests  B and  C were  due  to  the  fact  that  the 
furnace  was  not  permitted  to  cool  to  room  temperature  after 
Tests  A and  B. 


42 


SUPPLEMENTARY  FIRE  AND  HOSE  STREAM  TESTS 


Time 

in 

Temperature— 

-Degs.  Fa 

Minutes 

A 

B 

C 

0 

75 

430 

125 

5 

1060 

975 

975 

10 

1200 

1260 

1300 

15 

1415 

1400 

1425 

20 

1475 

25 

1500 

30 

1560 

There  were  no  significant  developments  during  the  exposure 
to  fire. 

Condition  of  Samples  After  Test — Sample  A,  exposed  to 
fire  for  30  min.,  and  to  the  hose  stream  for  4 seconds,  suffered 
considerable  damage  during  the  first  two  seconds  of  applica- 
tion of  the  stream  and  after  4 seconds  its  finish  coat  was  prac- 
tically all  washed  away,  about  one-half  the  brown  coat  was 
gone,  and  the  metal  lath  was  exposed  at  three  places  as  shown 
in  Fig.  22.  All  plaster  which  was  still  in  place  was  soft  and 
water  soaked. 

After  exposure  tO'  fire  for  15  min.,  and  to  the  hose  stream 
for  4 seconds,  the  finish  coat  of  sample  B was  washed  from 
about  three-fourths  the  area.  The  remaining  portion  of  the 
finish  coat  could  be  penetrated  easily  with  the  point  of  a knife 
blade,  but  calcination  was  not  complete.  The  brown  coat  was 
considerably  eroded  in  those  portions  where  it  was  uncovered 
by  the  removal  of  the  finish  coat.  It  was  soft  in  the  upper 
portion,  but  firm  in  the  lower  half  of  sample.  At  no  point  was 
the  scratch  coat  or  the  metal  lath  exposed.  Later  when  the 
brown  coat  was  removed,  the  scratch  coat  was  found  to  be 
soft  and  watersoaked  in  those  portions  of  the  sample  where 
the  brown  coat  was  soft.  The  appearance  of  the  sample  after 
test  is  shov/n  in  Fig.  23. 

After  being  exposed  to  fire  for  15  min.  and  to  the  hose 
stream  for  10  seconds,  practically  all  the  finish  coat  of  Sample 
C and  about  80%  of  the  brown  coat  were  washed  away.  The 
scratch  coat  was  carried  away  over  a considerable  area,  as  in- 
dicated in  Fig.  24.  All  plaster  remaining  in  place  was  water- 
soaked  and  very  soft. 

These  results  demonstrate  that  a construction  comprising 
gypsum  plaster  on  metal  lath  without  back-plaster  or  other 
finish  on  the  keys,  subjected  to  standard  fire  exposure  for  a pe- 
riod exceeding  30  min.,  loses  strength  through  calcination  suf- 
ficiently to  permit  the  impact  and  eroding  effect  of  standard 
hose  streams  to  remove  the  plaster  coating  so  that  water  may 
enter  freely  into  the  concealed  spaces  behind  the  lath. 


43 


Figure  22 

View  of  sample  A used  in  supplementary  Fire  and  Hose  Stream  Test 
after  exposure  to  standard  fire  conditions  for  30  min.,  when  a l^in. 
hose  stream,  30  lbs.  per  sq.  in.,  was  applied  for  two  periods  of  2 
seconds  each,  a total  of  4 seconds. 


Figure  23 

View  of  sample  B used  in  supplementary  Fire  and  Hose  Stream  Test 
after  sample  was  exposed  to  standard  fire  conditions  for  15  min., 
then  a 154-in.  hose  stream,  30  lbs.  per  sq.  in.,  was  applied  for  two 
periods  of  2 seconds  each  or  a total  of  4 seconds. 


44 


Figure  24 

View  of  sample  C used  in  supplementary  Fire  and  Hose  Stream 
Test,  after  sample  was  exposed  to  standard  fire  conditions  for  15 
min.,  then  a 1^-in.  hose  stream,  30  lbs.  per  sq.  in.,  was  applied  for 
five  periods  of  2 seconds  each  or  a total  of  10  seconds. 


45 


SECTION  II 


Retardant  No.  1355 

INTERIOR  FLOOR  AND  CEILING  CONSTRUCTION 
AS  A FIRE  RETARDANT 

Consisting  of 

Metal  Lath  and  G5rpsum  Plaster  on  Wood  Joists  With  Rough 
Wood  and  Finished  Flooring 

The  influence  of  floor  and  ceiling  construction  on  the  spread 
of  fire  within  buildings  is  of  importance.  Fire  resistive  proper- 
ties in  floor  construction  provide  a barrier  to  the  upward  spread 
of  fire  and  preserve  the  structural  integrity  of  a building  under 
fire  conditions.  Such  constructions  retain  these  properties 
under  service  conditions  incidental  to  the  ordinary  use  of 
the  buildings.  These  requirements  necessarily  involve  all  the 
parts  that  are  assembled  to  finish  or  effect  the  subdivision  of 
the  building  into  stories,  including  the  vertical  communications. 

This  report  deals  with  the  solid  or  unbroken  portion  of  the 
floor  areas  of  a representative  wood  joisted  floor  finished  on 
the  underside  with  metal  lath  and  gypsum  plaster.  It  de- 
velops mainly  the  fire  retardant  properties  secured  by  the  use 
of  this  construction. 

DESCRIPTION: 


GENERAL  CHARACTER 

The  floor  construction  forming  the  subject  of  this  report  is 
of  the  wood  joist,  expanded  metal  lath  and  gypsum  plaster 
pattern.  It  consists  of  the  wood  joist,  its  bridging,  the  rough 
wood  floor,  the  insulating  material,  the  furring  strips,  the 
finished  top  floor,  the  metal  lath,  its  fastenings,  the  gypsum 
plaster  finish.  The  finished  floors  vary  in  thickness,  depending 
on  the  spans  and  loads  they  are  designed  to  carry  and  are  de- 
signed to  be  used  for  buildings  of  any  area,  with  proper  lay- 
out of  girders  and  other  supports. 

The  wood  joists,  spaced  12  or  16  in.  on  centers,  usually  16 
in.,  are  supported  at  each  end,  in  some  cases  at  intermediate 
joints,  by  the  structural  members  of  the  building  upon  which 
they  rest.  The  bridging  is  between  the  joist  at  intervals  be- 
tween the  supports.  The  rough  flooring  is  nailed  directly  to 
the  top  of  the  joist  and  is  entirely  covered  by  the  insulating  ma- 
terial, which  is  in  turn  held  in  place  by  the  furring  strips  which 
are  located  over  the  joists  and  are  nailed  to  the  rough  floor- 


46 


DESCRIPTION 


ing.  The  tongue  and  grooved  top  flooring  covers  the  entire 
upper  surface  of  the  floor  and  is  nailed  to  the  furring  strips. 

The  metal  lath  is  attached  directly  to  the  bottom  edges  of 
the  joists  by  nails  or  staples  driven  into  the  joist.  The  gypsum 
plaster  finish  is  applied  in  three  coats  to  the  metal  lath  and  is 
^-in.  in  thickness. 

USE 

This  construction  is  regularly  used  in  buildings  of  fr:ir.ic 
or  ordinary  construction,  wherever  standard  fire  resisfi\  c c 
struction  is  not  required. 

DESCRIPTION  OF  PARTS 

Complete  description  of  parts  used  in  this  construction  is 
given  in  this  report  under  the  heading  “Examination  and  Test 
Record.’' 


INSTALLATION 

Complete  specifications  for  the  preparation  and  application 
of  metal  lath  and  gypsum  plaster  construction  on  wood  sup- 
ports is  given  in  Appendix  III. 

CLAIMS  MADE  BY  THE  SUBMITTORS 

Claims  for  this  construction  as  set  forth  by  the  Submittors 
are  given  in  Appendix  IV. 

OBJECT  OF  INVESTIGATION 

The  object  of  the  investigation  was  to  ascertain  the  value 
from  the  fire  protection  viewpoint  of  the  construction  described 
and  to  determine  its  classification  under  the  “Specification  for 
Standard  Fire  Tests  of  Materials  and  Construction,”  as  given 
in  Appendix  VII. 

PLAN  OF  INVESTIGATION 

The  general  features  of  the  investigation  covered  the  sub- 
jects of  Practicability,  Durability,  Strength  and  Uniformity,  as 
well  as  of  resistance  to  Fire  and  to  Fire  Hose  Streams  and 
Load  Tests. 

In  considering  these  subjects  the  features  of  Handling  and 
Shipping,  Preparation  for  and  actual  Installation,  Mainten- 


47 


FLOORS  AND  CEILINGS 


ance,  Wear  and  Tear,  Moisture,  Heat,  Flame  Resistance  and 
Heat  Resistance  were  severally  studied.  Data  covering  these 
features  and  properties  were  obtained  during  the  preparation  of 
specimens  for  tests,  during  the  actual  conduct  of  tests  and  in 
studies  of  the  specimens  and  their  units  after  tests. 

THE  FOLLOWING  TESTS  WERE  MADE 

Installation  Test 

Standard  Fire  Endurance  Test. 

Standard  Fire  and  Hose  Stream  Test. 

Excess  Load  Test. 

The  procedures  employed  in  these  tests  and  the  performance 
of  the  specimens  in  the  tests  are  reported  in  the  following  sec- 
tion entitled  “Examination  and  Test  Record.’' 

EXAMINATION  AND  TEST  RECORD 

A record  of  the  tests  and  examinations  made  is  given  in  this 
section  of  the  report. 


48 


INSTALLATION  TESTS: 


DESCRIPTION  OF  SAMPLES 

The  material  required  for  the  construction  of  the  floor  and 
ceiling  sample  consisted  of  the  following  units  which  were  fur- 
nished by  the  submittors. 

4 Joists,  2 by  12  in.  by  18  ft.  No.  1 rough  Southern  Yel- 
low Pine. 

17  Joists,  2 by  10  in.  by  14  ft.  No.  1,  Southern  Yellow  Pine. 

2 Boards,  1 by  10  in.  by  18  ft.  No.  1,  Southern  Yellow 
Pine. 

60  1^  by  3 in.,  No.  2 Yellow  Pine  bridging. 

48  Pieces,  1 by  6 in.,  No.  2 Yellow  Pine  rough  flooring. 

26  Pieces  2 by  2 Yellow  Pine  furring  strips. 

93  Pieces  1 by  4 in.,  B or  Better  dressed,  matched  Yellow 
Pine  flooring. 

1 Bundle  of  Cabot’s  Quilt. 

2 Bundles  No.  24  U.  S.  gauge  expanded  metal  lath  24  in. 
wide  and  96  in.  long. 

13  Bags  of  prepared  wood  fibered  gypsum  plaster. 

2 Bags  of  hydrated  lime. 

1 Bushel  of  hair. 

5 lb.  No.  12  annealed  wire. 

12  lb.  No.  18  annealed  wire. 

4 lb.  3^-in.  16-penny  wire  nails. 

5 lb.  2j4-in.  8-penny  wire  nails. 

6 lb.  2j4-in.  8-penny  wire  nails. 

6  lb.  2-in.  6-penny  wire  nails. 

METHODS 

The  test  panels  were  installed  so  as  to  All  the  opening  in 
the  top  of  one  of  the  standard  floor  test  furnaces  described  in 
Appendix  VI. 

The  test  panels  were  installed  as  nearly  as  possible  in  ac- 
cordance with  the  methods  advocated  by  the  submittors.  The 
wood  supports,  joists  and  flooring  were  installed  by  experienced 
carpenters  in  the  employ  of  a local  contractor,  under  the  di- 
rection of  a representative  of  the  National  Lumber  Manufac- 
turers’ Association.  The  metal  lath  and  plastering  was  in- 
stalled by  experienced  lathers  and  plasterers  in  the  employ  of 
a local  contractor,  under  the  direction  of  a representative  of 
the  Associated  Metal  Lath  Manufacturers.  All  the  work  was 
done  under  the  observation  of  the  Laboratories’  engineers. 

The  methods  of  installation  were  observed  during  and  after 
the  installation  of  the  test  panels  and  studied  in  connection 
with  the  drawings  and  specifications  submitted. 


49 


FLOORS  AND  CEILINGS 


RESULTS 

The  following  results  were  observed  during  and  after  the 
installation  of  the  samples. 

The  appearance  of  the  test  sample  during  and  after  in- 
stallation is  shown  by  Figs.  25  to  32  inclusive. 

Preparation  of  Materials — The  lumber  was  fairly  straight 
and  true  and  required  no  special  preparation  for  installation 
except  to  cut  to  the  desired  length.  The  sheets  of  metal  lath 
required  no  special  preparation  before  application  except  cut- 
ting to  the  desired  length  with  ordinary  snips.  The  plastering 
materials  were  delivered  to  the  Laboratories  and  stored  in  a 
clean,  dry  place  until  used.  Observations  indicate  that  the 
amount  of  preparation  necessary  depends  on  the  condition  of 
the  materials  when  they  are  received  at  the  job  and  the  pro- 
visions made  for  storing  the  same  until  they  are  ready  for  in- 
stallation. 

Installation  of  Woodwork — Details  are  shown  by  Figs.  25 
to  29  inclusive. 

Four  2 by  12-in.  rough  joist  were  cut  17  ft.  11  in.  long.  Two 
pieces  were  nailed  securely  together  by  3-in.  nails  and  in- 
stalled along  each  side  of  the  furnace  restraining  frame  resting 
on  four  metal  steel  stirrups  on  each  side.  The  2 by  10  dressed 
joists  were  cut  13  ft.  6 in.  in  length  and  installed  at  16-in.  cen- 
ters. 1^  by  3-in.  bridging  pieces  were  cut  and  installed  be- 
tween joists.  The  ends  of  the  channels  between  the  joists  were 
closed  by  nailing  a 1 by  10-in.  dressed  board  across  the  ends  of 
the  joists.  The  1 by  6-in.  rough  flooring  was  laid  contiguously 
and  transverse  to  the  joists  to  which  it  was  secured  by  2^-in. 
wire  nails,  two  nails  to  each  joist.  The  joints  between  the  ends 
of  the  boards  were  broken. 

The  quilt  was  applied  in  longitudinal  courses  lapping  at  the 
adjacent  edges  2^  to  5 in.,  averaging  about  3 in.  The  2 by 
2-in.  furring  strips  were  attached  over  the  quilt  around  the 
edges  of  the  panel  and  along  the  top  of  each  joist  and  was  se- 
curely attached  through  the  quilt  and  rough  flooring  joist  by 
3F2-in.  nails  driven  into  each  joist.  The  1 by  4-in.  dressed  and 
matched  flooring  was  laid  over  the  furring  strips;  2^-in.  cas- 
ing nails  were  used,  one  nail  to  each  furring  strip. 

Application  of  Metal  Lath — Details  are  shown  by  Figs.  26 
and  30. 

The  metal  lath  was  applied  to  the  under  side  of  the  joists 
in  longitudinal  courses,  beginning  along  the  junction  between 
the  wall  and  ceiling.  The  outer  sheets  were  bent  down!  so 
that  they  lapped  the  wall  joint  about  7 in.  Each  successive 
course  was  laid  so  that  the  edges  and  ends  overlapped  from  1 


50 


INSTALLATION  TESTS 


to  2 in.,  averaging  about  1)4  in.  The  transverse  joints  between 
sheets  were  broken. 

The  lath  was  attached  to  the  joists  by  2-in.  common  wire 
nails,  spaced  from  5 to  7 in.,  averaging  about  6 in.  The  nails 
were  driven  into  the  joist  about  in.  and  then  bent  across 
the  meshes  of  the  lath.  The  lath  was  attached  along  the  gyp- 
sum side  walls  of  the  furnace  combustion  chamber  by  2)4-in. 
common  wire  nails,  spaced  about  7)4-in.  centers  and  about  3 
in.  below  the  junction  of  the  wall  and  ceiling.  The  overlapped 
edges  were  tied  with  No.  18  annealed  wire  midway  between 
joists. 

Preparation  and  Application  of  Plaster — Details  are  shown 
by  Figs.  26  and  31. 

The  plaster  for  the  scratch  coat  was  prepared  in  an  ordinary 
mixing  box ; a layer  of  about  4 cubic  feet  of  the  prepared  wood 
fibered  gypsum  plaster  was  placed  in  the  box  and  about  lb. 
of  hair.  The  mixture  was  thoroughly  mixed  dry;  then  water 
was  added  to  the  desired  consistency.  The  mixture  was  then 
turned  several  times.  The  plaster  for  the  second  coat  was 
similar  to  the  first  coat  except  that  the  hair  was  omitted  in  this 
coat.  The  finishing  coat  was  composed  of  hydrated  lime  and 
prepared  gypsum  plaster  with  the  fiber  removed  and  was  mixed 
in  about  the  proportion  of  one  to  one. 

Nails  were  attached  to  the  under  side  of  the  joist  to  serve 
as  a gauge  for  the  plaster.  These  nails  were  removed  before 
the  finish  coat  was  troweled  to  a uniform  surface. 

The  first  coat  of  plaster  was  applied  lightly  but  with  suffi- 
cient pressure  to  force  it  well  through  the  mesh,  to  imbed  the 
metal  lath  and  form  full  keys.  Sufficient  plaster  was  next  ap- 
plied to  cover  thoroughly  the  lath  and  extend  from  to  ys-in. 
outside  the  lath.  After  this  coat  had  set  for  a few  minutes  its 
surface  was  thoroughly  scratched  in  both  directions  with  the 
edge  of  a piece  of  the  metal  lath. 

After  the  scratch  coat  had  dried  for  about  18  hours,  the 
brown  coat  was  applied.  Sufficient  plaster  was  spread  on  to 
bring  the  coating  out  nearly  flush  with  the  nails  and  the  sur- 
face was  then  made  straight  and  true  with  a rod  and  darby, 
but  was  left  rough  under  the  tools  to  furnish  a bond  for  the 
finish  coat. 

After  the  brown  coat  had  dried  for  about  two  days  the 
finish  coat  was  applied.  The  surface  of  the  brown  coat  was 
first  sprinkled  with  water  and  a thin  coat  of  the  plaster  was 
then  thoroughly  troweled  on,  applying  enough  plaster  to  cover 


51 


FLOORS  AND  CEILINGS 


the  brown  coat  completely.  Enough  additional  plaster  was  then 
applied  to  make  the  surface  straight  and  true.  The  surface 
was  then  gone  over  again  with  the  material  as  thin  as  it  could 
be  handled  and  all  imperfections  worked  out  and  the  coating 
troweled  and  brushed  to  a smooth,  uniform  surface. 

The  observations  made  by  the  engineers  showed  that  if  or- 
dinary facilities  are  provided  these  plasters  can  be  properly 
handled  and  mixed  by  workmen  reasonably  familiar  with  this 
class  of  work.  The  mixing  box  must  be  tight  and  of  ample  size 
for  the  batches  used  and  the  workmen  must  understand  the 
imporfance  of  obtaining  the  proper  proportions  and  of  prompt 
completion  of  the  batch  mixes,  of  clean  tools,  and  of  avoiding 
the  use  of  mixed  plaster  that  has  commenced  to  set. 

Maintenance — The  observations  during  the  construction  of 
the  floor  indicate  that  the  materials  are  of  such  a form  and  so 
arranged  that  the  injured  portions  can  be  removed,  replaced 
and  repaired,  and  that  the  repaired  portions  will  be  practically 
equivalent  to  new  work. 

Durability  and  Strength — Observations  during  the  installa- 
tion of  the  floor  and  a study  of  the  design  and  construction  in- 
dicate that  these  floors  are  capable  of  withstanding  all  ordi- 
nary influences  for  long  periods,  except  moisture  and  tempera- 
tures above  200  deg.  The  secure  manner  in  which  the  various 
materials  are  assembled  and  attached,  and  the  known  prop- 
erties of  the  materials  indicate  that  these  floors  are  capable  of 
withstanding  all  ordinary  stresses  to  which  they  are  likely  to  be 
subjected  in  the  classes  of  building  for  which  they  are  advo- 
cated. 

Uniformity — The  observations  during  the  installation  indi- 
cate that  the  materials  are  made  with  a fair  degree  of  uniform- 
ity and  that  they  can  be  installed  in  a satisfactory  manner  in 
the  field  by  workmen  having  a reasonable  amount  of  expe- 
rience with  material  of  this  character. 


52 


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53 


underwriters  laboratories  R.1505 


Figure  27 

View  of  joist  assembly  and  cross  bridging  before  flooring  and  metal 
lath  and  gypsum  plaster  ceiling  were  installed.  View 
looking  west  into  top  of  furnace. 


Figure  28 

View  showing  the  top  flooring  installed,  the  layout  of  targets  for 
measuring  deflections  and  layout  of  tubes  for  inserting  thermocouples 
into  joist  bay  spaces.  Brick  load  not  yet  applied.  View  looking 
west  at  top  of  furnace. 


54 


Figure  29 

View  of  joist  bridging  and  underside  of  rough  flooring  taken  before 
installation  of  the  metal  lath,  looking  west  and  upwards  into  com- 
bustion chamber  space  before  chamber  side  walls  were  built  in. 


Figure  30 

View  showing  metal  lath  installed  and  plaster  not  yet  applied.  View 
looking  west  and  upward  into  furnace  chamber,  the  west  wall  of 
which  is  built  in  except  for  the  temporary  opening  at  center.  Ob- 
serve lapping  of  lath  down  side  wall. 


55 


Figure  31 

View  showing  plaster  finish  installed;  also  showing  thermocouples 
3 and  4 in  place.  View  looking  west  upward  and  into  combustion 
chamber  showing  observation  windows  mounted  in  west  wall. 


Figure  32 

View  of  Floor  and  Ceiling  Construction  before  and  after  test,  with 
rated  load  of  50  lbs.  per  sq.  ft.  in  place,  showing  deflection  targets 
and  thermocouples  wired  to  junction  box.  View  looking  west  across 

top  of  furnace. 


56 


FIRE  ENDURANCE  TEST: 


DESCRIPTION  OF  SAMPLE 

The  test  was  made  in  accordance  with  the  provisions  of  the 
Standard  Specifications  for  Fire  Tests  of  Building  Materials 
and  Construction.  The  test  specimen  was  installed  in  the  fur- 
nace as  previously  described  and  as  shown  by  the  illustrations 
Figs.  25  to  31  inclusive.  The  design  of  the  furnace  is  described 
in  Appendix  VI  of  this  report. 

Object  of  Test — The  object  of  the  test  was  to  determine  the 
condition  of  the  construction  at  the  expiration  of  the  test  pe- 
riod required  for  a one-hour  classification.  Accordingly  the 
test  was  continued  for  one  hour  and  15  min.,  the  specified  ex- 
tended period  for  a 1-hr.  classification  (80%  of  75  min.  equals 
60  min.,  1 hr.). 


METHOD  OF  TEST 

The  test  specimen  installed  as  previously  described  was 
allowed  to  remain  in  position  for  30  days  after  application  of 
the  gypsum  plaster  ceiling  finish.  During  this  period  the  fur- 
nace was  housed  with  wood  sheathing  protecting  the  construc- 
tion from  severe  weather  variations.  Salamanders  placed  at 
outside  corners  of  the  furnace  and  within  the  frame  enclosure 
assisted  in  preventing  undue  absorption  of  atmospheric  moist- 
ure. Five  days  previous  to  the  fire  test  the  floor  construction 
was  loaded  with  fire  brick  placed  to  provide  a uniform  loading 
of  50  lbs.  per  sq.  ft.  This  loading  corresponds  to  the  recog- 
nized loading  for  joisted  floor  constructions  like  the  specimen 
considered  in  this  report.  Deflections  were  measured  from 
level  readings  of  the  targets  mounted  on  the  specimen.  Read- 
ings taken  before  and  after  this  load  was  applied  and  during 
and  at  the  conclusion  of  the  test. 

The  Fire  Endurance  Test  was  made  on  the  afternoon  of 
Thursday,  April  6,  1922.  Representatives  of  the  submittors  at- 
tended. The  temperatures  within  the  furnace  were  regulated  by 
means  of  gas  and  air  control  valves  and  were  maintained  in 
close  agreement  with  the  Standard  Time  Temperature  Control 
Curve. 

Observations  were  made  during  the  test  of  the  distribution 
and  general  character  of  the  fire,  the  color  of  the  ceiling  finish 
due  to  heat  and  of  the  combustion  chamher  pressures. 

Observations  were  made  throughout  the  test  period  cover- 
ing the  flame  retarding  properties  of  the  construction  as  indi- 
cated by  appearance  of  smoke  and  flame  through  the  plaster 
finish,  the  formation  of  cracks  or  larger  openings  permitting  the 
passage  of  flame  into  the  hollow  construction,  the  passage  of 
smoke  and  flame  through  the  sample  and  the  extent  of  flame 
passage  and  of  combustion  at  the  conclusion  of  the  test. 


57 


FLOORS  AND  CEILINGS 


Observations  were  made  during  and  after  the  test  covering 
the  heat  insulating  properties  of  the  construction  by  thermo- 
couples placed  within  the  joist  spaces  and  adjustable  in  a 
vertical  plane,  and  by  the  condition  of  the  materials  after  test. 

Observations  were  also  made  during  and  after  the  test  cov- 
ering the  effect  of  the  fire  exposure  provided  by  the  test  condi- 
tions on  the  stability  of  the  construction  as  indicated  by  de- 
velopment of  cracks,  bulging,  spalling,  calcination  or  other 
evidence  of  insecurity  and  by  the  condition  of  the  structural 
parts  after  the  test. 

At  the  conclusion  of  the  75-min.  period  the  furnace  fire  was 
shut  off  and  the  joist  bay  spaces  were  sprayed  with  water, 
thereby  extinguishing  incipient  fire,  if  any,  within  the  hollow 
construction.  This  permitted  subsequent  study  of  the  fire  dam- 
age to  the  combustible  units  of  the  assembly  and  determination 
of  residual  structural  strength.  Results  of  Fire  Endurance 
Test,  Figs.  32  to  40  inclusive,  show  condition  of  the  assembly 
and  its  units  following  the  test. 

RESULTS 

The  following  observations  were  made  during  the  test  and 
after : 

Character  of  Fire — The  fire  was  well  distributed  throughout 
the  combustion  chamber  during  the  entire  75  min.  period. 
Strong  jets  of  flame  impinged  directly  upon  the  ceiling  sur- 
face from  each  of  the  burners  throughout  the  period.  The  com- 
bustion chamber  was  completely  filled  with  a thin  luminous 
flame  for  practically  the  entire  period.  The  temperatures  read 
on  the  couples  within  the  combustion  chamber  were  as  shown 
in  Fig.  41.  The  curves  show  that  the  average  temperatures 
were  slightly  above  but  in  close  agreement  with  the  standard 
curve  for  the  entire  test  period. 

Flame  Resistance — The  ceiling  surface  was  under  observa- 
tion during  the  entire  test  period  without  occurrences  worthy 
of  note,  except  a north  and  south  fire  crack  in  the  approximate 
center  which  was  noted  before  test  and  which  became  slightly 
enlarged  at  50  min.,  and  a series  of  waves  in  the  plaster  sur- 
face during  the  last  10  min.  of  the  period. 

No  openings  were  formed  in  the  ceiling  finish  which  per- 
mitted the  passage  of  flame  into  the  hollow  construction. 

On  the  upper  face  of  the  test  panel  steam  was  noted  at 
40  min.,  and  continued  to  issue  in  small  volume  during  the 
remainder  of  the  test.  At  50  min.  a slight  odor  of  smoke  mixed 
with  steam  was  detected,  but  this  odor  was  not  very  marked 
at  any  time  during  the  remainder  of  the  test. 


58 


FIRE  ENDURANCE  TEST 


The  water  dislodged  the  greater  part  of  the  brown  and  fin- 
ished coat  after  test,  also  the  weight  of  the  water  pulled  the 
lath  slightly  from  position  on  its  supports. 

The  condition  of  the  metal  lath  and  gypsum  plaster  finish 
after  test  is  shown  b}^  Figs.  36  to  39  inclusive. 

These  observations  indicate  that  when  in  good  condition 
and  exposed  to  fire  that  has  passed  the  incipient  stage  and  in- 
volves freely  burning  material  in  the  interior  of  a building, 
wood  joist  floor  construction  finished  on  the  under  side  with 
metal  lath  and  three-coat  ^-in.  fibered  gypsum  plaster,  will 
serve  as  an  effective  barrier  to  passage  of  flame  through  the 
joist  assembly  for  considerably  more  than  one  hour.  Under 
most  conditions  the  construction  will  serve  to  prevent  such 
flame  passage  until  the  attachments  fail  and  collapse  takes 
place.  - Fire  will  be  transmitted  by  conduction  to  the  wood 
supports  and  other  combustible  material  in  the  hollow  spaces 
of  the  construction  before  the  finish  fails  by  the  formation  of 
openings. 

Heat  Resistance — The  observations  on  the  top  of  the  floor 
indicated  that  the  transmission  of  heat  through  the  test  sample 
was  very  slight  throughout  the  test.  The  general  appearance 
of  the  unexposed  face  at  1 hr.  15  min.  was  practrcally  as  before 
test.  The  highest  temperature  reading  of  the'  thermometer 
mounted  on  the  upper  face  of  the  top  flooring  whs  100  deg.  F. 
at  73  min. 

Observations  of  the  lower  face  of  the  sample;  failed  to  de- 
velop the  exact  points  at  which  transmission  of  heat  through 
the  plaster  ceiling  most  affected  the  wood  supports.  The  tem- 
peratures as  taken  between  the  joist  bays  about  two  inches 
away  from  the  back  face  of  the  exposed  finish  are  shown  by 
Fig.  41.  The  locations  of  the  thermocouples  are  shown  by  Fig. 
32,  numbering  from  north  edge  of  panel.  Couples  marked  No. 
5 and  8 which  were  installed  in  the  middle  of  joist  way  No.  6 
.and  9,  respectively,  from  the  north  edge  of  panel,  showed  the 
highest  temperatures.’ 

Observations  indicate  that  when  this  construction  is  in  good 
condition  and  exposed  to  fire  that  has  passed  the  incipient  stage 
and  involves  freely  burning  material  in  the  interior  of  build- 
ings, the  heat. insulating  property  of  the  finish  is  sufficient  to 
prevent  the  transmission  of  fire  to  the  wood  supports  back  of 
it  for  about  45  min.,  and  that  the  passage  of  fire  into  or  through 
the  assembly  will  occur  by  transmission  of  heat  through  the 
finish  by  conduction  before  openings  are  formed  in  the  finish 
that  will  permit  the  passage  of  flame. 


59 


Figure  331 

View  o£  Floor  and  Ceiling  Construction  after  Fire  Endurance  Test, 
looking  north  at  top  of  furnace.  Brick  load  and  top  flooring  re- 
moved, showing  condition  of  2 by  2 in.  furring  strip  and  of  the  in- 
sulation. Rough  floor  in  the  center  strip  was  removed  after  test  to 
permit  inspection  of  joist  and  joist  bay  spaces. 


Figure  34 

View  of  Floor  and  Ceiling  Construction  after  Fire  Endurance  Test, 
looking  south  at  top  of  furnace.  Brick  load  and  top  flooring  re- 
rempval.  Observe  that  darkened  portion  at  west  is  from  shadow  of 
furnace  roof  and  not  from  effects  of  Fire  Test. 


60 


Figure  35 

View  of  Floor  and  Ceiling  Construction  after  Fire  Endurance  Test, 
looking  south  into  top  of  furnace.  A close-up  of  the  under-sides  of 
the  rough  flooring,  showing  smoke  and  heat  stains.  Boards  in  same 
relative  position  as  during  test. 


Figure  36 

View  of  Floor  and  Ceiling  Construction  after  Fire  Endurance  Test, 
looking  west  into  top  of  furnace,  showing  brick  load  and  flooring 
removed  and  the  general  condition  of  the  joist  and  bridging. 


61 


FLOORS  AND  CEILINGS 


Deflection — The  deflection  at  the  middle  of  the  panel  before 
test  was  0.20  in.  in  120  hrs.  after  the  uniformly  distributed  load 
of  50  lbs.  per  sq.  ft.  was  applied,  or  about  one-half  of  the  com- 
puted deflection.  During  the  Fire  Endurance  Test  this  deflec- 
tion increased  to  a total  of  1.08  in.  at  75  min.,  when  the  furnace 
fire  was  extinguished.  The  total  deflection  after  the  water  was 
applied  was  1.48  in.,  which  decreased  to  1.18  in.  five  days  after 
the  brick  load  was  removed. 

FIRE  AND  HOSE  STREAM  TEST: 

A Fire  and  Hose  Stream  Test  was  not  made  in.  the  case 
of  the  construction  under  consideration  in  view  of  the  Fire  and 
Hose  Stream  Tests  made  on  metal  lath  and  gypsum  plaster 
mounted  on  vertical  wood  supports,  which  are  fully  described  in 
Section  I of  this  report.  Also  in  addition  to  these  tests  a Stand- 
ard Fire  and  Hose  Stream  Test  was  previously  made  on  a wood 
joist  floor  construction  similar  to  that  under  consideration, 
except  that  portland  cement  plaster  was  used  instead  of  gyp- 
sum plaster  for  the  ceiling  finish.  These  tests  are  fully  de- 
scribed in  Appendix  I. 


Figure  37 

Flooring  and  Ceiling  Construction  after  Fire  Endurance  Test.  Close- 
up  view  looking  into  top  of  furnace  (southeast  quarter);  showing 
condition  of  joist,  bridging  and  plaster  finish  after  test  in  the  area 
where  the  damage  to  these  members  was  most  marked. 


62 


Figure  38 

View  of  Floor  and  Ceiling  Construction  subjected  to  75-min.  exposure 
to  standard  Fire  Endurance  Test.  This  photograph  shows  arrange- 
ment of  parts  comprising  the  construction. 


f)3 


Figure  39 

View  of  Floor  and  Ceiling  Construction  after  Fire  Endurance  Test, 
looking  into  furnace  chamber.  The  plaster  fell  from  position  after 
the  furnace  fire  was  shut  off  and  water  had  been  sprayed  into  joist 
spaces  above  the  metal  lath  and  plaster  ceiling  assembly. 


EXCESS  LOAD  TEST: 

The  sample  employed  for  this  test  was  of  a construction  like 
the  sample  covered  by  this  report,  except  that  ^-in.  three-coat 
Portland  cement  plaster  ceiling  finish  was  used  instead  of  gyp- 
sum plaster. 

METHOD 

The  sample  was  loaded  with  common  brick,  50  lbs.  per  sq. 
ft.,  then  subjected  to  standard  fire  conditions  for  45  min.,  and 
immediately  subjected  to  a Standard  Hose  Stream  Test  con- 
sisting of  1^-in.  stream  of  water,  30  lbs.  per  sq.  in.,  for  5 min., 
following  which  it  was  allowed  to  cool  and  then  subjected  to 
two  and  one-half  times  the  safe  rated  load,  or  125  lbs.  per  sq. 
ft.,  as  specified  in  the  Standard  Specifications  for  Fire  Tests  of 
Materials  and  Construction  described  in  Appendix  VII. 

An  account  of  this  test  and  the  results  are  given  in  Appendix 
I,  Fire  and  Hose  Stream  Test  and  Excess  Load  Test. 


64 


Figure  40 

Floor  and  Ceiling  Construction  after  75-min.  exposure  to  Standard  Fire  En- 
durance Test.  Section  of  joist  No.  4 (Fig.  37)  showing  maximum  charring 
at  lower  edge  of  joist.  Original  dimensions  It^s  by  954  in.  (dressed),  nom- 
inally 2 by  10  in. 


66 


SECTION  III 

SERVICE  RECORD 

The  fairly  general  use  of  metal  lath  as  a base  for  plaster 
coatings  extends  over  a period  in  excess  of  a quarter  century, 
during  which  period  many  instances  of  satisfactory  perform- 
ance under  various  fire  conditions  have  occurred.  A detailed 
statement  of  record  in  service  seems  unnecessary  in  this  report 
in  view  of  the  general  familiarity  with  its  uses  and  perform- 
ance. 

SUPERVISION  OF  PRODUCT  BY  UNDERWRITERS^ 
LABORATORIES: 

It  is  contemplated  that  standards  for  metal  lath  correspond- 
ing to  the  material  used  in  the  construction  of  the  test  samples 
described  herein  shall  be  drawn  up  and  applied  to  the  products 
of  the  several  members  of  the  submitting  association. 

Inspection  at  factories  and  labeling  of  standard  metal  lath 
permitting  its  identification  wherever  used  is  under  considera- 
tion. 

The  Submittors  will  enter  into  a contract  with  the  Lab- 
oratories for  the  Reexamination  Service  permitting  systematic 
observance  of  the  service  record  of  the  construction  covered 
by  this  report. 


CONCLUSIONS 

Metal  lath  on  wood  supports  serving  as  a base  for  gypsum 
plaster  on  the  inside  of  buildings  is  sometimes  employed  as  a 
single  finish  on  ceilings,  as  in  attics  and  side  walls.  When  em- 
ployed for  corridor  and  room  partitions,  for  walls  and  for  en- 
closures to  vertical  openings  the  usual  practice  is  to  finish  each 
side  of  the  partition,  wall  or  enclosure.  General  considerations 
of  practicability,  durability,  strength  and  uniformity  may  be 
discussed  in  common  for  single  or  double  finish  and  are  so 
treated  in  the  following.  From  the  fire  retarding  viewpoint 
the  test  results  emphasize  a material  variation  in  performance. 
Accordingly  individual  discussion  and  rating  of  single  and 
double  finish  construction  involving  metal  lath  and  gypsum 
plaster  and  of  the  wood  joisted  floor  and  ceiling  construction 
is  essential. 

PRACTICABILITY: 

Metal  lath,  the  lumber  and  the  other  materials  employed  can 
be  handled  for  shipment  and  at  buildings  without  fear  of  break- 
age or  other  material  injury,  and  can  be  installed,  renewed  and 
repaired  in  the  manner  advocated  without  difficulty  by  ordinary 


67 


CONCLUSIONS 


workmen,  and  without  serious  impairment  of  structural  fea- 
tures or  of  the  fire  retarding  properties  of  the  final  assembly. 

The  gypsum  plaster  and  other  ingredients  for  the  plaster 
coating  require  no  special  care  or  treatment  in  handling,  ship- 
ping or  installation  beyond  that  regularly  given  to  these  ma- 
terials generally.  The  mixing  and  application  can  readily  be 
performed  in  the  manner  advocated,  which  differs  in  no  es- 
sential respect  from  that  regularly  employed. 

The  conclusions  are  indicated  by  the  results  of  observations 
made  before  and  during  the  Installation  Tests  and  from  com- 
mon knowledge  of  field  practice  and  from  the  service  record. 

DURABILITY: 

• 

Excessive  free  moisture  and  frequent  or  continued  exposure 
to  temperatures  in  excess  of  200  deg.  F.  cause  deterioration  and 
calcination  of  gypsum  plaster  coatings.  A construction  employ- 
ing this  plaster  should  not  be  advocated  for  such  conditions. 
In  other  respects  the  gypsum  plaster  coating,  like  the  lumber 
and  the  metal  lath,  is  capable  of  resisting  all  ordinary  deterior- 
ating influences  for  long  periods. 

The  service  record  of  this  construction,  the  known  proper- 
ties of  the  materials  comprising  it  and  field  experience  confirm 
such  a conclusion  as  to  durability  drawn  from  observations 
made  during  the  Installation  and  subsequent  tests  described  in 
this  report. 

STRENGTH: 

The  wood  stud  and  wood  joist  construction  under  consid- 
eration, including  the  fabricated  metal  reinforcement  which 
provides  a positive  key  for  the  plaster,  possesses  ample  strength 
for  the  uses  considered  and  will  withstand  without  failure  or  ma- 
terial damage  all  ordinary  stresses  or  loads  to  which  it  may  be 
subjected  under  the  service  conditions  likely  to  be  met  with  in 
the  class  of  buildings  for  which  they  are  advocated.  The  heat 
insulating  value  of  the  gypsum  plaster  preserves  the  combust- 
ible load  bearing  units  from  ignition  for  fairly  long  periods 
under  standard  fire  exposure  conditions. 

This  conclusion  is  based  upon  the  known  properties  of  ma- 
terials and  upon  field  observations,  the  service  record  and  the 
fire  endurance  and  the  load  tests. 

UNIFORMITY: 

No  unusual  care  or  precision  is  required  to  ensure  practi- 
cal uniformity  of  assembly,  security  or  performance  in  the  con- 
structions. 


68 


FIRE  RETARDANT  PROPERTIES 


The  metal  lath,  the  lumber  and  other  materials  employed 
in  the  constructions  are  capable  of  close  control  as  to  quality 
of  material,  weight  and  other  dimensions.  The  installation  and 
assembly  of  materials  and  the  plaster  coating  is  capable  ot 
control  to  a sufficient  degree  and  proper  measures  of  control 
are  commonly  employed  in  the  plastering  and  other  building 
trades. 

FIRE  RETARDING  PROPERTIES: 

SINGLE  FINISH 

As  a single  finish,  metal  lath  on  wood  supports  and  with  a 
%-in.  three-coat  gypsum  plaster  coating  when  exposed  on  the 
finished  side  to  standard  fire  test  conditions,  will  delay  active 
combustion  of  its  wooden  supports  for  about  45  min.,  after 
which  period  it  will  continue  to  prevent  the  passage  of  flame 
through  the  finish  up  to  at  least  one  hour’s  total  fire  exposure. 
Upon  application  of  a standard  fire  hose  stream,  during  or  im- 
mediately following  fire  exposure,  the  fire  retarding  properties 
of  such  a single  finish  will  be  almost  entirely  destroyed  after 
30  min.  of  such  fire  exposure. 

DOUBLE  FINISH 

When  installed  on  both  sides  of  a partition  frame  or  wall 
frame  of  wood  studs,  the  construction  either  may  serve  as  non- 
bearing or  may  be  called  upon  to  bear  a certain  proportion  of 
both  dead  and  live  loads  from  the  floors  above.  The  following 
conclusions  are  based  upon  the  assumption  in  either  case  that 
complete  flre-stopping  within  hollow  spaces  is  provided : — 

NON-BEARING  PARTITIONS  OR  WALLS— Metal  lath 
with  5^-in.  three-coat  gypsum  plaster  coatings  when  installed  on 
each  side  of  the  wood  studs  comprising  the  framework  of  non- 
bearing partitions  or  walls  which  are  exposed  on  one  side  to 
standard  fire  test  conditions  will  prevent  the  passage  of  fire 
through  the  partition  or  wall  for  upwards  of  one  hour  and  will 
function  as  a barrier  to  passage  of  flame  and  spread  of  fire  for 
at  least  one  hour  when  subjected  on  one  side  to  the  impact  and 
erosion  of  standard  fire  hose  streams  applied  any  time  up  to 
one  hour  from  the  beginning  of  the  fire  exposure  period.  The 
fact  that  the  combustible  frame  of  the  partition  or  wall  will  be 
burning  within  the  1-hr.  period  (about  45  min.)  should  have 
consideration,  but  does  not  detract  from  the  performance  of 
the  construction  as  a fire  retardant  up  to  the  limiting  period. 

BEARING  PARTITION  OR  WALL— Metal  lath  with 
%-in.  three-coat  gypsum  plaster  coatings  when  installed  on  each 
side  of  studs  comprising  the  framework  of  bearing  partitions  or 


69 


CONCLUSIONS 


walls  and  when  exposed  on  one  side  only  to  standard  fire  test 
conditions  will  prevent  the  passage  of  fire  through  the  partition 
or  wall  for  the  entire  period  during  which  studding  of  the  di- 
mensions ordinarily  employed  (2  by  4 in.  or  2 by  6 in.)  will  sup- 
port its  load.  After  45  min.  exposure  on  one  side  to  standard 
fire  test  conditions  reduction  of  section  and  loss  of  strength  of 
the  wood  supports  from  charring  and  from  active  combustion 
takes  place.  The  construction,  when  employed  as  a bearing 
partition  or  wall,  will  function,  while  loaded,  as  a barrier  to 
the  passage  of  flame  and  spread  of  fire  for  at  least  1 hr.  when 
subjected  on  one  side  to  impact  and  erosion  by  standard  fire 
hose  streams  applied  any  time  up  to  1 hr.  from  the  beginning 
of  the  fire  exposure  period.  The  fact  that  the  combustible 
frame  of  the  partitions  or  wall  will  be  ignited  in  about  45  min. 
of  fire  exposure  should  have  consideration,  but  does  not  de- 
tract from  the  performance  of  the  construction  as  a whole  as 
a fire  retardant  up  to  the  limiting  period. 

This  conclusion  is  based  upon  the  results  of  the  Fire  En- 
durance Tests  and  the  Fire  and  Hose  Stream  Tests,  and  upon 
the  evidence  of  the  readings  for  bulging  or  distortion  in  the 
Fire  Endurance  Tests  to  the  effect  that  no  strains  were  placed 
upon  the  load  bearing  members  because  of  expansion  effect  of 
heat  on  these  members,  the  m.etal  lath  or  the  plaster  coat. 

A construction  employing  wood  studs,  stills,  plates,  braces 
and  similar  units  is  quite  generally  permitted  for  relatively 
light  loads,  as  in  residences,  as  a bearing  wall  or  partition. 
When  loaded  not  to  exceed  50  lbs.  per  sq.  ft.  of  supported  floor 
area  (for  2 by  4-in.  studs  on  16-in.  centers)  calculations  (see 
“Claims  Made  by  the  Submittor’’  in  Appendix  IV)  show  a fair 
factor  of  safety  which  may  be  taken  into  consideration  in  con- 
nection with  the  extent  of  fire  damage  to  the  wooden  sup- 
ports. The  panel  used  for  the  Eire  and  Hose  Stream  Test  was 
subjected  to  a standard  fire  exposure  for  45  min.,  promptly 
whereupon  the  hose  stream  was  applied,  extinguishing  all  fur- 
ther burning  of  the  wood  frame.  Examination  then  made 
showed  the  edges  of  studs  on  the  side  of  the  panel  exposed  to  the 
fire  charred  in  places  to  a depth  of  %.  in.  The  opposite  edges 
and  the  sides  of  the  studs  were  not  yet  affected,  although  it 
was  evident  that  the  ignition  point  had  been  nearly  reached. 

The  panel  used  in  the  Eire  Endurance  Test  No.  2 was  sub- 
mitted to  a standard  fire  exposure  for  75  min.,  promptly  where- 
upon the  hose  stream  was  applied,  extinguishing  all  further 
burning  of  the  wood  frame.  Examinations  then  made  showed 
that  the  edges  of  the  studs  on  the  side  of  the  panel  exposed  to 
the  fire  were  charred  from  a mere  discoloration  to  a depth  of 
W in.  in  places.  The  opposite  edge  was  not  yet  affected,  but 


70 


STABILITY  AND  FIRE  STOPPING 


the  sides  were  charred  slightly  near  the  exposed  edge  where 
the  charring  was  most  markedly  on  the  exposed  face. 

Other  calculations  (see  Claims  Made  by  the  Submittor) 
show  reasonably  high  factors  of  safety  remaining  when  char- 
ring has  occurred  to  a depth  of  % in.  on  two  faces  of  studs.  On 
this  basis  and  in  view  of  the  fact  that  the  strength  of  the  un- 
charred portion  of  the  cross  section  of  a v/ood  stud  remains 
practically  unimpaired,  and  in  view  of  the  fact  that  material  ex- 
pansion under  heat  and  contraction  upon  cooling  are  not  proper- 
ties of  wood,  of  which  material  the  load  bearing  units  of  this 
construction  are  made,  a conclusion  relating  to  fire  retarding 
properties  of  the  construction  when  loaded  may  properly  be 
made  if  based,  upon  the  observed  condition  at  the  end  of  the 
Fire  Endurance  Test  No.  2 or  the  period  before  active  burning 
of  the  wooden  supports  had  begun.  This  direct  and  possibly 
severe  basis  for  such  a conclusion  is  necessarily  employed  since 
apparatus  for  testing  walls  or  partitions  under  standard  fire 
test  conditions  and  while  bearing  rated  loads  is  not  available 
at  the  plant  of  Underwriters’  Laboratories,  and  data  covering  re- 
sults of  such  test,  if  any,  made  elsewhere,  is  not  available. 

Wood  Joist  Floor  and  Ceiling  Construction — The  following 
conclusions  .are  based  upon  the  assumption  that  complete  fire 
stopping  within  the  hollow  spaces  is  provided. 

A wood  joist  floor  construction  utilizing  a metal  lath  and 
gypsum  plaster  ceiling  finish,  when  exposed  on  the  ceiling 
side  to  standard  fire  test  conditions,  will  for  at  least  one  hour 
safely  sustain  its  rated  load  and  suffer  no  serious  reduction  of 
strength  or  of  cross  section  area  of  combustible  load  bearing 
units  and  will  prevent  the  passage  of  fire  through  the  assembly 
for  at  least  one  hour  unless  previously  subjected  on  the  ceiling 
side  to  the  impact  and  eroding  effect  of  standard  hose  streams. 
Upon  application  of  hose  streams  after  30  min.  standard  fire  test 
exposure  the  gypsum  plaster  finish  will  be  destroyed.  The  fact 
that  the  combustible  units  of  the  construction  will  be  burning 
within  the  1-hr.  period  (about  45  min.)  should  have  considera- 
tion, but  does  not  detract  from  the  performance  of  the  assembly 
as  a fire  retardant  up  to  the  limiting  period. 

These  conclusions  are  based  on  the  Fire  Endurance  Tests 
and  Eire  and  Hose  Stream  Tests  as  outlined  in  previous  chap- 
ters of  this  report. 

A floor  construction  employing  wood  joists  is  quite  gen- 
erally recognized  for  relatively  light  loads  as  in  residence,  of- 
fice and  small  mercantile  occupancies.  When  loaded  not  to  ex- 
ceed 50  lbs.  per  sq.  ft.,  2 by  10  in.  joists,  16-in.  centers,  show  a 
fair  factor  of  safety  (See  Claims  Made  by  Submittors),  which 


71 


CONCLUSIONS 


may  be  taken  into  consideration  in  connection  with  the  extent 
of  the  fire  damage  to  the  wood  joist. 

The  sample  used  in  the  Fire  Endurance  Test  was  subjected 
while  loaded,  50  lbs.  per  sq.  ft,  to  standard  fire  conditions  for 
75  min.  Promptly  thereupon  water  was  applied,  extinguishing 
all  further  burning  of  the  wood  members.  Examination  then 
made  showed  the  edges  of  the  joist  exposed  to  the  fire  charred 
in  places  to  a depth  of  3%  in.  The  sides  of  the  joist  adjacent 
to  the  exposed  edge  were  also  charred  and  the  remainder  of 
the  sides  of  the  joist  and  underside  of  the  rough  flooring  were 
discolored  and  slightly  charred  in  a few  spots.  In  view  of  the 
fact  that  the  strength  of  the  uncharred  portion  of  the  section 
of  the  wood  joist  remains  practically  unimpaired,  a conclusion 
relating  to  the  fire  resisting  properties  of  the  construction  when 
loaded  may  properly  be  made  if  based  on  the  observed  con- 
dition at  the  end  of  the  Fire  Endurance  Test. 

The  regularly  adopted  Standard  Specifications  for  Eire 
Tests  of  Materials  and  Construction  contemplate,  dn  the  case 
of  floor  constructions,  that  test  specimens  shall  be  subjected  to 
fire  exposures  from  the  ceiling  side  only.  This  procedure  has 
been  followed  in  this  case  and  the  retardant  classification  pro- 
posed is  on  that  basis  and  the  foregoing  conclusion  is  so  stated. 

STABILITY: 

The  constructions  under  consideration  comprising  metal  lath 
and  gypsum  plaster  on  wood  supports  will  develop  the  fire  re- 
tarding classifications  assigned  elsewhere  in  this  report  when 
the  metal  lath  is  supported  by  the  6-penny  2-in.  nails  for  ceil- 
ings and  4-penny  nails  or  1^-in.  staples  spaced  on  an 

average  of  6 in.  for  partitions  (and  without  supplementary  at- 
tachments as  originally  contemplated,  see  Appendix  I). 

Observations  during  and  after  tests  both  upon  partition  and 
wall  specimens  and  upon  the  floor  construction,  show  practical 
absence,  in  the  case  of  specimens  having  gypsum  plaster  coat- 
ings, of  serious  bulging,  cracking  or  spalling,  the  effects  of  ex- 
pansion forces  due  to  temperature  rise. 

WHEN  FIRE  STOPPING  IS  OMITTED: 

Mention  has  previously  been  made  of  “fire-stopping”  as  a 
basic  condition  of  the  foregoing  conclusions  relating  to  the 
fire  retarding  properties  of  constructions  comprising  metal  lath 
and  gypsum  plaster  on  wood  supports.  In  every  case  assemblies 
exposed  to  standard  fire  endurance  and  to  fire  and  hose  stream 
tests  as  described  in  this  report  were  completely  firestopped. 


72 


STABILITY  AND  FIRE  STOPPING 


In  this  respect  the  test  conditions  approximated  ideal  conditions 
and  were  far  superior  to  representative  good  fire  stopping  as 
done  in  the  field.  Absence  of  fire  stopping  will  have  no  influ- 
ence upon  the  fire  retarding  performance  of  the  constructions 
considered  in  this  report  up  to  the  point  when  ignition  of  the 
combustible  wood  supports  takes  place.  Thereafter  without 
fire  stopping  the  progress  of  fire  within  concealed  spaces  will 
be  impeded  very  slightly,  if  at  all,  by  the  nature  of  the  units 
employed  in  the  described  assemblies.  The  Fire  Endurance 
Test  No.  2,  and  the  Fire  and  Hose  Stream  Test  of  the  wall  and 
partition  constructions  and  the  Fire  Endurance  Test  of  the 
» floor  construction  utilizing  gypsum  plaster  show  incipient  char- 
ring of  wood  supports  at  about  45  min.  standard  fire  test  ex- 
posure. 

When  fire  stopping  is  omitted  the  constructions  covered  by 
this  report  utilizing  metal  lath  ^and  gypsum  plaster  on  wood 
supports  will  resist  an  exposure  from  standard  fire  test  condi- 
tions for  35  min.  before  ignition  of  combustible  material  in  con- 
cealed spaces  will  occur. 


73 


SECTION  IV 

APPENDIX  I 

Retardant  No.  1355 
August  10,  1922 

BRIEF  SUMMARY  OF  TESTS 

ON 

WOOD  JOIST  FLOOR  CONSTRUCTION 

WITH 

Metal  Lath  and  Portland  Cement  Plaster  Ceiling  Finish 

Associated  Metal  Lath  Manufacturers, 

Chicago,  111. 

National  Lumber  Manufacturers’  Association 
Chicago,  111.  Washington,  D.  C. 

Joint  Submittors 

GENERAL: 

The  following  is  a brief  summary  of  the  results  of  Fire  En- 
durance, Fire  and  Hose  Stream  Test  and  Excess  Load  Tests 
on  Wood  Joist  Floor  Construction  with  a Metal  Lath  and 
Portland  Cement  Plaster  Ceiling  Finish.  In  other  respects  the 
samples  were  constructed  practically  similar  to  the  samples  de- 
scribed in  Section  11.  The  test  program  followed  the  Standard 
Specifications  for  Fire  Tests  of  Materials  and  Construction  de- 
scribed in  Appendix  VII. 

FIRE  ENDURANCE  TEST: 

DESCRIPTION  OF  SAMPLE 

The  sample  was  constructed  similar  to  that  described  for 
the  Fire  Endurance  Test  of  the  gypsum  plaster  construction, 
except  that  the  pieces  of  No.  8 annealed  wire  about  30  in.  long 
were  bent  in  the  form  of  a loop  and  inserted  over  the  second 
joist  from  each  end  of  the  room  and  over  each  joist  2 ft.  from 
the  east  and  west  walls  and  along  the  middle  joist.  The  loops 
were  spaced  at  2 ft.  centers  on  each  of  the  two  joists  along 
the  second  joist  from  each  end  and  along  middle  joist.  They 
engaged  the  metal  lath  and  were  intended  to  support  the  ceil- 
ing finish  in  case  the  nails  or  staples  pulled  as  the  result  of 
expansion  forces  under  test  conditions. 

The  Portland  cement  plaster  was  applied  in  three  coats  ac- 
cording to  the  usual  practice  for  portland  cement  plaster  on 
metal  lath.  The  proportion  was  three  parts  of  sand  and  one  of 
Portland  cement  with  an  allowance  of  10  per  cent  of  hydrated 
lime  to  the  weight  of  portland  cement.  A small  amount  of  ani- 


74 


FIRE  ENDURANCE  TEST 


mal  hair  was  used  in  the  first  coat.  The  finish  was  about 
in  thickness. 

The  sample  was  29  days  old  when  tested  and  had  been  allowed 
to  season  for  21  days  in  freely  circulating  air  inside  a wooden 
building;  was  subjected  to  ordinary  autumn  weather  in  this 
locality,  from  October  18  to  November  16,  1920,  where  it  was 
possible  for  the  temperatures  to  go  below  the  freezing  point 
for  the  short  periods  during  the  latter  part  of  the  seasoning 
period.  From  the  21st  to  the  25th  day  of  the  seasoning  period 
the  sample  was  dried  by  two  salamanders  installed  on  the 
outer  side  of  the  sample  and  the  heat  was  directed  through  an 
opening  in  east  and  west  wall  into  the  chamber  which*  con- 
tained the  cement  finish.  The  heat  was  circulated  into  the  in- 
terior by  two  electric  fans.  During  the  last  four  days  the  side 
walls  were  closed  up  and  the  wooden  building  was  removed 
in  order  to  apply  the  brick  load.  After  the  brick  load  was  ap- 
plied several  longitudinal  hair  cracks  were  noted  in  finished 
ceiling.  The  largest  of  these  cracks  extended  the  full  length 
of  the  ceiling  about  55  in.  from  the  east  wall.  Another  broken 
series  of  longitudinal  cracks  were  noted  in  north  portion  of 
the  ceiling.  The  width  of  these  cracks  did  not  exceed  1-32  of 
an  inch  at  any  point. 

The  appearance  of  the  test  panel  with  the  load  applied  be- 
fore test  is  shown  by  Fig.  42. 

METHOD 

The  standard  test  equipment  described  in  Appendix  VI  was 
used  in  this  test. 

The  test  sample  was  subjected  to  a uniformly  distributed 
live  load  of  50  lbs.  to  the  sq.  ft.  This  load  consisted  of  new  com- 
mon Chicago  brick  piled  in  rows  spaced  about  ^ in.  apart. 

The  apparatus  for  measuring  furnace  pressures  and  tempera- 
tures and  for  measuring  deflections  in  the  test  panel  were  in- 
stalled and  the  fire  started.  The  lower  face  of  the  test  panel 
was  exposed  to  the  standard  fire  conditions  in  which  the  tem- 
perature was  raised  to  approximately  1550  deg.  F.  during  the 
first  30  min.  to  approximately  1700  deg.  F.  at  the  end  of  1 hr., 
and  then  gradually  upward  until  the  end  of  the  test. 

The  test  was  continued  for  1 hr.  and  35  min.  when  the  fire 
in  the  furnace  was  extinguished,  this  being  approximately  30 
min.  longer  than  1 hr.  period  for  which  classification  was  de- 
sired. 

The  top  of  the  test  panel  was  flooded  with  water  from  a 
small  stream  in  an  effort  to  extinguish  the  fire  in  the  hollow 
spaces  and  to  permit  detailed  examinations  of  the  parts,  a 
portion  of  the  east  wall  of  the  furnace  was  knocked  out  to  per- 
mit access  for  extinguishing  the  fire.  A hole  was  also  punched 
through  the  metal  lath  and  plaster  in  an  effort  to  render  the 


75 


• APPENDIX  I— FLOORS  AND  CEILINGS 


interior  accessible  for  extinguishing  of  the  fire,  but  the  fire 
on  the  interior  continued  to  burn  until  the  floor  collapsed. 

Observations  were  made  during  and  after  the  test  covering 
the  distribution  and  general  character  of  the  fire,  the  color  of 
the  parts  due  to  heat,  the  deflection  of  the  test  panel,  and  the 
pressures  and  temperatures  in  the  furnace,  to  obtain  informa- 
tion relative  to  the  effect  of  the  fire  on  the  strength  of  the 
parts  and  the  floor  and  its  flame  and  heat  resistance. 

RESULTS 

The  following  is  a summarization  of  the  results  observed 
during  and  after  the  test: 

The  appearance  of  the  test  panel  before  and  after  the  test 
is  shown  by  Figs.  42  and  43.  The  average  indicated  tempera- 
tures in  the  furnace  are  shown  by  the  curve  in  Fig.  44. 

Character  of  Fire — The  fire  was  clear  and  semi-luminous 
during  the  first  30  min.,  but  was  somewhat  unevenly  distributed 
during  this  period,  the  exposure  being  more  severe  in  the  north 
half.  The  fire  was  clear  and  luminous  and  uniformly  distrib- 
uted during  the  remainder  of  the  test.  The  surface  of  the 
panel  began  to  show  color  in  spots  at  20  min.,  was  dull  red 
in  all  parts  at  30  min.,  became  bright  red  at  60  min.  and  re- 
mained so  until  after  the  gas  was  shut  off  at  95  min.  No  pres- 
sure above  atmosphere  was  noted  in  the  furnace  during  the 
test.  The  average  furnace  temperatures  were  slightly  below  the 
standard  temperatures  and  are  shown  by  the  time-temperature 
curve  in  Fig.  44. 

After  the  gas  was  turned  off,  long  luminous  flames  issued 
from  the  cracks  in  the  plaster,  nearly  filling  the  furnace  with 
flame.  This  continued  intermittently  for  probably  in  excess  of 
30  min.  The  fire  continued  to  burn  in  the  hollow  spaces  until 
the  floor  collapsed  at  about  2^  hrs.  after  the  start  of  test. 

Cracks,  Spalling,  Bulging  and  Deflection — The  finish  coat 
of  plaster  commenced  to  spall  off  min.  after  the  fire  was 
started  and  continued  to  be  thrown  off  at  various  parts  of  the 
sample,  until  7 min.,  when  about  one-quarter  of  the  finish  coat 
was  off  in  patches  of  various  sizes  in  several  parts  of  the  panel, 
the  largest  single  dislodgement  being  about  3 by  7 ft.  in  the 
north  half.  The  scratch  and  second  plaster  coats  remained 
in  place  until  the  end  of  the  test  and  were  apparently  well 
bonded,  together  and  to  the  lath. 

At  30  min.  a crack  was  noted  extending  east  and  west 
clear  across  the  panel  close  to  the  middle,  and  at  35  min.  a 
diagonal  crack  about  14  in.  long  was  noted  near  the  southeast 
corner.  At  50  min.  2 longitudinal  cracks,  18  to  24  in.  long, 
were  noted  between  the  middle  crack  across  the  middle,  at  55 
min.  another  north  and  south  crack  appeared  in  the  locality 
and  at  80  min.  still  another,  the  latter  being  near  the  middle 


76 


FIRE  ENDURANCE  TEST 


of  the  panel.  These  cracks  were  undoubtedly  body  cracks  and 
became  gradually  wider  as  the  bulging  increased,  and  were  ap- 
parently about  in.  wide  at  the  surface  of  the  plaster  at  90 
mih. 

At  35  min.  the  lath  and  plaster  coating  was  bulging  down- 
ward slightly,  near  the  southeast  corner,  and  at  40  min.  the 
plaster  coating  was  irregularly  bulged,,  the  bulging  being  most 
marked  in  the  south  half  where  it  amounted  to  about  2 in. 
Irregular  bulging  increased  to  a maximum  of  about  3 in.  at  the 
cracks  at  50  min.  At  60  min.  irregular  bulging  had  reached  a 
maximum  of  about  in.  in  the  north  half  and  about  4 in.  in 
the  south  half.  The  maximum  downward  bulging  was  at 
points  approximately  midway  between  the  supporting  wires. 

The  deflection  of  the  floor  at  the  middle  of  the  panel  before 
test  was  0.11  in.,  72  hrs.  after  a uniformly  distributed  live  load 
of  50  lbs.  to  the  sq.  ft.  was  applied,  or  about  0.34  in.  less  than 
the  computed  deflection.  After  the  fire  was  started  the  de- 
flections gradually  increased  to  1.86  in.  exclusive  of  initial  de- 
flection when  the  fire  was  extinguished.  This  increase  in  de- 
flection was  nearly  coincident  with  the  appearance  of  bulging. 

The  condition  of  the  assembly  after  test  is  shown  by  Fig.  43. 

Flame  Resistance — On  the  upper  face  of  the  test  panel, 
steam  issued  from  a slight  crack  in  the  floor  boards  at  43  min. 
Steam  was  also  noted  east  of  the  middle  and  in  the  northwe.st 
corner  of  the  panel  during  the  45  to  55  min.  period,  continuing 
to  issue  .at  these  points  during  the  test.  At  60  min.  slight 
smoke  was  noted  at  the  above  points  and  also  in  the  southwest 
corner.  At  75  min.  smoke  issued  along  the  north  and  south 
edges  and  at  85  min.  along  the  east  and  west  edges  of  the  test 
panel.  The  smoke  issued  at  these  points  during  the  remainder 
of  the  1-hr.  35  min.  period  when  the  furnace  was  in  operation. 
It  increased  very  much  in  volume  at  the  edges  of  the  panel  after 
this  period  until  the  end  of  the  test.  At  about  hrs.  after 
the  test  was  started,  slight  flame  was  noted  near  the  middle  of 
the  west  edge  of  the  panel.  This  flame  was  intermittent,  came 
from  the  fire  on  the  interior  of  the  floor,  and  issued  through 
a separation  at  the  fire  stop  at  the  ends  of  the  joist  caused  by 
the  marked  sagging  of  the  floor  at  this  period.  The  test  panel 
collapsed  under  the  load  at  about  2^  hrs. 

The  entire  wooden  floor  was  practically  consumed  except 
small  sections  of  the  flooring,  furring  strips,  joist  and  insulation 
along  the  edges  and  ends.  The  wooden  girders  along  each 
side  of  the  restraining  frame  were  in  normal  condition,  the 
two  joist  along  the  north  and  south  side  of  the  restraining 
frame  were  only  charred  about  in.  along  the  side.  This 
good  condition  was  due  to  the  protection  afforded  by  the  6-in. 


77 


APPENDIX  I— FLOORS  AND  CEILINGS 


gypsum  blocks  which  were  placed  in  the  outside  of  these 
members. 

On  examination  of  the  sample  after  test,  the  finished  coat 
was  practically  all  knocked  off  except  small  areas  along  the 
sides  and  edges.  The  other  two  coats  were  badly  cracked  but 
appeared  to  have  retained  most  of  their  original  strength.  A 
good  key  was  formed  in  the  back  face  of  the  lath  and  aver- 
aged about  34  in.  in  thickness,  which  formed  an  irregular  coat 
of  plaster  on  the  back  face  of  the  entire  ceiling.  These  keys, 
reinforced  by  the  metal  lath,  apparently  strengthened  the  finish 
to  a considerable  extent. 

The  metal  lath  was  separated  longitudinally  of  the  ceiling. 
This  separation  was  due  to  the  reinforcing  wires  separating  and 
allowing  the  ceiling  to  collapse  in  two  sections.  The  metal 
lath  appeared  in  good  condition,  but  the  reinforcing  wires  be- 
came annealed  at  two  points  and  pulled  apart,  due  to  the  heal 
and  excessive  load  which  they  were  called  on  to  carry  aftei 
the  joist  had  collapsed.  These  separations  were  formed  mid- 
way of  each  of  the  north  and  west  walls  of  the  sample.  The 
loops  and  other  parts  of  the  reinforcing  wires  appeared  to  hold 
their  position  in  all  cases. 

The  observations  on  the  exposed  face  of  the  panel  indicated 
that  no  flame  passed  into  the  hollow  spaces  and  that  the  joist 
and  wooden  members  were  ignited  by  the  transmission  of 
heat  rather  than  the  passage  of  flame.  The  time  at  which  the 
joist  took  fire  could  not  be  ascertained,  although  it  is  probable 
that  this  occurred  within  about  60  min.  A tar-like  substance 
was  noted  running  down  on  the  outside  wall  of  the  furnace  in 
the  southwest  corner  at  65  min.  and  considerable  smoke  issued 
from  the  underside  of  the  panel  in  this  corner  at  70  min.  THe 
edges  of  the  cracks  in  the  plaster  were  also  blackened  by  tar 
or  similar  substance  distilled  out  of  the  wood  at  about  this 
period  and  remained  so  until  the  furnace  fire  was  shut  off  at 
95  min.  The  floor  was  apparently  well  afire  on  the  inside  at 
this  time  as  long  gas  flames  issued  from  all  cracks  and  filled 
the  furnace  chamber  with  flame,  although  all  other  fuel  was 
shut  off.  The  fire  in  the  furnace  chamber  was  extinguished 
by  a small  hose  stream  applied  at  short  intervals  for  over  hr., 
but  the  gases  generated  by  the  fire  on  the  interior  of  the  floor 
reignited  by  contact  with  the  heated  furnace  during  this  pe- 
riod unless  the  stream  of  water  was  almost  constantly  applied. 
A small  hole  was  punched  through  the  lath  and  plaster  near 
the  east  side  of  the  panel  at  about  2 hrs.  and  fire  was  discovered 
on  the  interior.  Under  these  conditions  it  was  found  imprac- 
ticable to  remove  sufficient  lath  and  plaster  to  permit  ex- 
tinguishment of  all  of  the  fire  in  the  woodwork,  so  it  was  al- 


78 


Figure  42 

View  of  sample  mounted  in  furnace  ready  for  Fire  Endurance  Test 
with  load  of  50  lbs.  per  sq.  ft.  applied,  showing  deflection  targets 
and  furnace  thermocouples  connected  up  to  junction  box  ready 

for  test. 


Figure  43 

View  looking  west  in  furnace,  showing  condition  of  floor  after  col- 
lapse of  sample  into  the  furnace  chamber. 


79 


APPENDIX  I— FLOORS  AND  CEILINGS 


lowed  to  burn  until  the  floor  collapsed  about  2^  hrs.  after  the 
start. 

Heat  Resistance— The  observations  on  top  showed  that  the 
transmission  of  heat  through  the  assembly  was  very  slight 
throughout  the  entire  test.  The  general  appearance  of  this 
face  of  the  panel  when  the  gas  was  shut  off  at  1 hr.  and  35  rnin. 
was  practically  the  same  as  before  the  test,  except  that  sufficient 
heat  passed  through  the  floor  at  the  points  where  steam  and 
smoke  were  noted  to  melt  patches  of  snow  and  dry  off  the 
boards  in  one  small  area. 

After  the  furnace  was  shut  off  a small  stream  of  water  was 
applied  to  the  upper  side  so  that  it  would  leak  through  the 
boards  and  aid  in  the  extinguishing  of  the  burning  interior. 
This  water  settled  to  the  middle  and  was  retained  to  a depth  of 
3 or  4 in.  for  some  time,  adding  to  the  load  on  the  floor.  The 
"bricks  also  absorbed  considerable  water  and  thus  still  further 
increased  the  live  load. 


80 


FIRE  AND  HOSE  STREAM  TEST: 


DESCRIPTION  OF  TEST  SAMPLE 

The  test  sample  employed  in  this  test  was  constructed  prac- 
tically identical  with  and  was  mounted  in  the  same  manner  as 
the  panel  used  in  the  Fire  Endurance  Test.  It  was  44  days 
old  when  tested  and  had  received  the  same  treatment  as  the 
panel  previously  described  except  that  four  salamanders  were 
kept  going  on  the  outside  of  the  test  sample  during  and  for 
four  days  after  the  installation  of  the  plaster,  in  order  to  keep 
the  temperatures  above  the  freezing  point  as,  this  sample  was 
allowed  to  season  from  February  14  to  March  30,  1921.  The 
sample  was  firm  and  apparently  in  a normally  dry  condition  and 
free  from  cracks  or  visible  separations*  likely  to  affect  its  fire 
resistance.  The  finish  on  the  ceiling  averaged  about  % in.  in 
thickness  on  the  outer  surface  of  the  lath. 

The  average  length  of  the  finished  floor  was  17  ft,  5^  in. 
and  the  average  width  of  the  floor  was  13  ft,  634  in. 

The  average  length  of  the  finished  ceiling  exposed  to  the 
fire  was  15  ft,  734  and  the  average  width  was  11  ft.,  in. 

The  appearance  of  the  test  sample  before  test  with  the 
brick  load  applied  is  shown  in  Fig.  45. 

METHODS 

The  Laboratories’  standard  test  equipment  described  in  Ap- 
pendix VI  was  used  in  this  test. 

The  test  panel  was  subjected  to  uniformly  distributed  live 
load  of  50  lbs.  per  sq.  ft.  This  load  consisted  of  common  Chi- 
cago brick  piled  in  rows  spaced  about  34  in.  apart. 

A specially  designed  ^-in.  open  sprinkler  arrangement  was 
provided  at  each  end  of  each  joistway  during  the  installation. 
This  was  installed  to  overcome  the  difficulty  experienced  with 
the  Fire  Endurance  Test  sample  which,  due  to  lack  of  some 
method  of  extinguishing  fire  in  the  joist  ways,  was  practically 
consumed  in  the  test. 

The  test  sample  was  subjected  to  the  standard  fire  test  for 
45  min.,  after  which  the  gypsum  walls  along  the  east  and  west 
wall  were  torn  away  and  a in.  stream  of  water  applied  to 
the  heated  face  of  the  plaster  finish  for  about  5 min.  The 
stream  was  applied  from  about  12  ft.  from  the  center  of  the 
panel  and  about  3 ft.,  6 in.  below  its  ceiling  surface.  It  was 
first  directed  at  the  middle  of  the  sample  and  then  at  all  parts 
of  the  exposed  face,  changes  in  the  direction  of  the  stream 
being  made  slowly.  The  pressure  at  the  base  of  the  nozzle 
was  45  lbs.  per  sq.  in.  throughout  the  test. 

Observations  were  made  throughout  the  fire  test  covering 
the  distribution  and  general  character  of  the  fire,  the  color  of 
the  test  panel  due  to  heat,  the  deflection  of  the  test  panel,  the 


81 


APPENDIX  I— FLOORS  AND  CEILINGS 


furnace  pressures  and  temperatures  in  the  furnace  and  at  seven 
points  within  the  construction  which  were  symmetrically  spaced, 
one  near  the  middle  of  the  center  joistway  and  one,  two  joist- 
ways  on  either  side  of  the  middle  point.  The  other  four  tem- 
peratures were  taken  at  the  quarter  points  between  the  second 
and  third  joistway  from  each  end  of  the  sample. 

Observations  were  made  during  and  after  the  test  to  ob- 
tain information  relative  to  the  effect  of  the  fire  and  water 
on  the  strength  of  the  parts  and  the  floor  as  a whole  and  rela- 
tive to  flame  and  heat  resistance. 

• RESULTS 

The  following  results  were  observed  during  and  after  the 
test,  the  developments  relating  to  each  feature  and  the  con- 
clusions drawn  therefrom  being  given  under  their  respective 
headings. 

The  appearance  of  the  test  panel  before  and  after  test  is 
shown  by  Figs.  45  to  56  inclusive. 

The  average  indicated  temperatures  in  the  furnace  and  in 
the  joistways  is  shown  by  Fig.  57. 

Character  of  Fire — The  fire  was  fairly  well  distributed  over 
the  under  face  of  the  sample  throughout  the  test.  It  was  some- 
what less  severe  on  the  edges  than  at  the  middle  and  during 
the  first  part  of  the  test  it  was  most  intense  over  the  burners. 
Falling  plaster  partially  choked  several  burners  directly  below 
the  portions  of  the  panel  from  which  the  plaster  fell.  There 
was  very  little  direct  impinging  of  stiff  flame  jets  on  the  panel, 
although  this  was  noticeable  for  short  periods  when  the  burn- 
ers were  first  lighted. 

The  fire  was  semi-luminous  for  the  first  15  min.  of  the  test, 
generally  clear  but  smoky  in  places  during  the  15  to  20  min.  pe- 
riod, clear  during  the  20  to  25  min.  period  and  generally  clear 
filling  the  chamber  from  that  time  on.  The  panel  was  lumin- 
ous in  spots  at  10  min.,  showed  a trace  of  color  all  over  in  ten 
min.,  dull  red  all  over  with  brighter  spots  in  20  min.  and  red 
all  over  with  soot  spots  in  25  min.  As  the  test  progressed  the 
color  became  brighter  and  the  spots  gradually  disappeared. 

Cracks,  Spalling,  Bulging  and  Deflections — The  plaster  coat- 
ing commenced  to  spall  at  8 min.,  throwing  off  the  plaster  fin- 
ish from  an  area  about  3 ft.  wide  and  8 ft.  long,  exposing  the 
metal  lath  and  apparently  allowing  fire  to  enter  the  hollow 
spaces  between  the  joist.  Another  explosion  occurred  at  13  min. 
increasing  the  original  opening  into  the  interior.  A slight 
bulge  was  noted  at  20  min.  No  other  cracks  or  separations 
were  noted  during  the  test. 


82 


FIRE  AND  HOSE  STREAM  TEST 


The  deflection  at  the  middle  of  the  sample  was  0.20  in.  88 
hrs.  after  the  load  of  50  lbs.  per  sq.  ft.  was  applied  or  about 
0.20  in  less  than  the  computed  deflection. 

During  the  test  the  deflection  not  including  the  deflection 
before  test,  gradually  increased  to  about  0.51  in.  at  45  min., 
when  the  furnace  fire  was  shut  off  and  the  deflection  after  the 
water  stream  was  applied  was  0.88  in.,  and  was  0.91  in.  after 
the  sample  was  allowed  to  cool  for  22  hrs.  Five  days  after  the 
load  of  50  lbs.  per  sq.  ft.  was  removed,  the  total  deflection  was 
0.82  in.,  including  the  deflection  before  test. 

Flame  Resistance — When  the  test  had  been  in  progress  8 
min.,  there  was  a muffled  explosion  and  the  plaster  forming  all 
but  the  scratch  coat  fell  off  of  an  area  estimated  to  be  8 ft.  long 
and  3 ft.  wide.  The  scratch  coat  fell  off  in  spots  inside  this 
area  exposing  the  metal  lath  in  several  places  and  apparently 
permitting  flame  to  enter  the  concealed  space  between  the 
joists.  At  13  min.  there  was  another  explosion  and  consider- 
ably more  lath  was  exposed  and  the  area  from  which  plaster 
had  dropped  increased  to  some  extent.  At  no  time  during  the 
tests  were  any  cracks  visible  in  the  sample  or  any  separations 
or  dislodgements  other  than  those  mentioned.  At  20  min.  the 
panel  appeared  to  have  a slight  general  bulge  and  the  surface 
appeared  somewhat  irregular. 

The  application  of  the  stream  washed  away  all  of  the  finish 
coat  of  plaster  and  increased  the  area  of  exposed  lath  but  did 
not  throw  off  any  large  pieces.  Except  the  finish  coat  and  the 
part  previously  loosened  by  fire,  the  remaining  plaster  re- 
mained securely  in  position.  The  special  sprinkler  arrange- 
ment installed  between  joists  was  operated  after  the  wat 'r 
stream  was  applied  and  all  burning  parts  were  extinguished 
in  the  hollow  spaces  at  about  55  min. 

On  the  unexposed  side  of  the  sample  steam  appeared  around 
the  outer  edge  of  the  sample  at  7 min.,  appearing  at  other  points 
at  10  min.  and  increasing  in  volume  at  30  min.,  when  con- 
siderable steam  was  issuing  along  the  south  edge  adjacent  to 
the  area  where  the  plaster  had  fallen  from  p,osition.  A slight 
odor  of  burning  wood  was  apparent  from  the  south  edge  of 
the  sample  at  15  min.  and  slight  traces  of  smoke  mixed  with 
steam  were  noted  at  20  min.  A slight  increase  in  the  volume 
of  this  steam  and  smoke  was  noted  along  the  south  edge  of 
the  sample  during  the  remainder  of  the  test. 

There  was  no  apparent  passage  of  flame  through  or  around 
the  sample  during  the  test. 

The  condition  of  the  unexposed  side  of  the  sample  after  test 
is  shown  by  Figs.  45  and  47. 

On  examination  of  sample  after  test  and  during  the  dis- 
mantling of  the  same,  the  finished  floor  was  found  only  slightly 


83 


APPENDIX  I— FLOORS  AND  CEILINGS 


discolored  in  the  south  edges  where  steam  and  smoke  passed 
around  the  outer  edges  between  the  restraining  frame  of  the 
furnace  and  test  sample.  Slight  scorching  of  the  under  side 
of  the  finished  floor  was  noted  immediately  above  the  insula- 
tion where  the  plaster  fell  from  position.  The  nails  held  their 
position  in  all  cases. 

The  condition  of  the  finished  floor  after  the  brick  load  was 
removed  is  shown  by  Fig.  47. 

The  furring  strips  were  undamaged  and  remained  in  posi- 
tion but  were  slightly  discolored.  The  condition  of  the  furring 
strips  after  test  is  shown  by  Fig.  48. 

The  insulation  appeared  in  normal  condition  after  test  ex- 
cept immediately  above  the  area  where  the  fire  charred  the 
rough  flooring.  The  condition  of  the  insulation  after  test  is 
shown  by  Figs.  48  and  56. 

The  rough  flooring  was  in  normal  condition  except  in  the 
areas  where  the  plaster  was  dislodged.  The  charring  in  the 
damaged  area  varied  from  a mere  discoloration  to  a complete 
charring  at  two  points  between  joistways  four  and  five  from 
the  south  edge  of  the  sample. 

The  condition  of  the  rough  flooring  after  test  is  shown  by 
Figs.  49  and  50  inclusive. 

The  bridging  was  completely  charred  in  the  damaged  area 
and  the  fire  stream  washed  away  part  of  the  charred  sections. 
The  bridging  in  the  remaining  sections  of  the  floor  was  normal 
in  appearance  and  held  its  position  in  all  cases. 

The  joist  was  charred  from  a mere  discoloration  along  the 
sides  of  the  joist  to  almost  45  per  cent  of  the  total  cross  sec- 
tional area  where  the  fire  first  broke  through  the  cement  plaster 
finish.  A permanent  maximum  downward  deflection  of  in. 
was  noted  near  the  middle  of  the  center  joist  and  gradually  de-. 
creasing  toward  each  end  of  the  sample. 

The  condition  of  the  joist  and  bridging  after  test  is  shown 
by  Figs.  51  to  53  inclusive. 

After  the  test  the  metal  lath  and  portland  cement  plaster 
bulged  slightly  away  from  the  under  side  of  the  joist  except 
where  the  finish  was  reinforced  and  held  in  position  by  the 
loops  which  were  attached  over  the  top  of  the  joist.  A slight 
bulge  was  noted  between  the  wire  loops;  the  maximum  being 
almost  in.  near  the  middle  of  the  center  joist.  The  nails 
securing  the  lath  to  the  joist  pulled  from  position  in  the  joist 
inside  the  area  reinforced  by  the  heavy  wire.  The  maximum 
deflection  of  the  finish  away  from  the  joist  was  4l4  in.  in  dam- 
aged area. 


84 


FIRE  AND  HOSE  STREAM  TEST 


A good  key  was  formed  on  the  back  face  of  the  lath  which 
was  covered  in  all  cases  with  the  scratch  coat  mortar.  The  en- 
tire finish  coat  was  spalled  or  washed  off  during  the  test.  The 
other  two  coats  were  firm  and  apparently  retained  the  greater 
part  of  their  original  strength  except  in  the  spalled  area.  The 
plaster  contained  several  small  surface  cracks  in  the  area  where 
the  plaster  remained  in  position.  Small  cracks  were  noted  at 
the  junction  between  the  wall  and  ceiling,  but  these  did  not 
allow  fire  to  enter  the  interior  of  the  floor;  the}^  were  not  con- 
sidered serious  from  a fire  protection  viewpoint. 

The  condition  of  the  ceiling  after  test  is  shown  by  Figs.  52 
to  55  inclusive. 

Heat  Resistance — The  extent  of  the  heat  insulation  afforded 
by  the  plaster  was  not  clear  from  observation  on  the  fire  side, 
but  it  was  noticeable  that  very  little  smoke  or  gas  reached  the 
furnace  chamber  from  interior  of  the  sample.  It  appeared  that 
the  falling  plaster  must  have  exposed  the  wood  work  at 
about  8 min.  and  the  exposed  metal  lath  was  red  hot  at  15 
min.  The  temperatures  in  the  sample  are  shown  by  Fig.  57. 


85 


EXCESS  LOAD  TEST: 

DESCRIPTION  OF  SAMPLE 

The  test  sample  used  in  the  Fire  and  Flose  Stream  Test 
was  used  in  this  test.  The  brick  load  was  removed  and  the 
sample  was  allowed  to  stand  for  about  five  days. 

The  condition  of  the  sample  after  the  removal  of  the  brick 
load  used  in  the  Fire  and  Water  Test  and  before  the  excess 
load  of  125  lbs.  per  sq.  ft.  was  applied  is  shown  by  Fig.  47. 

METHODS 

The  test  sample  was  subjected  to  a uniformly  distributed 
live  load  of  125  lbs.  per  sq.  ft.  This  load  consisted  of  common 
Chicago  brick  piled  in  rows  spaced  about  % in.  apart  both 
ways. 

Readings  were  taken  at  1 hr.,  after  loads  of  50  lbs.,  100  and 
125  lbs.  per  sq.  ft.  were  applied  and  again  after  the  load  had 
been  applied  about  46  hrs.  and  16  hrs.  after  the  load  was  re- 
moved from  the  sample. 

Observations  were  made  during  and  after  the  application  of 
the  excess  load  to  obtain  information  relative  to  the  following 
features,  strength  of  parts  as  indicated  by  the  brick  load  sus- 
tained, the  deflection  under  load,  the  development  of  cracks, 
insecurity  in  attachments  or  other  evidence  of  weakness  and 
by  the  condition  of  the  floor  after  the  load  was  applied  and 
removed. 


RESULTS 

The  following  results  were  observed  during  the  progress  of 
the  test  and  examination  afterwards. 

The  appearance  of  the  floor  before  and  after  the  excess  load 
was  applied  is  shown  in  Fig.  47  and  the  appearance  of  the 
sample  with  the  load  applied  is  shown  by  Fig.  46. 

The  sample  assumed  a permanent  set  after  the  initial  fire 
test  loading  (50  lbs.  per  sq.  ft.)  of  0.82  in.  and  this  permanent 
set  is  not  included  in  the  following  computation. 

The  deflection  at  the  middle  of  the  sample  one  hr.  after 
the  application  of  a live  load  of  50  lbs.  per  sq.  ft.  was  0.24  in., 
100  lbs.  per  sq.  ft.  was  0.44  in.  and  125  lbs.  per  sq.  ft.  was  0.49 
in.  and  the  total  deflection  after  the  load  had  been  applied  46 
hrs.  was  0.57  in.  The  reading  16  hrs.  after  the  load  was  re- 
moved was  0.07. 

A slightly  greater  deflection  was  recorded  in  the  area  directly 
above  the  point  where  the  finish  was  dislodged  and  the  joist 
was  exposed  to  the  direct  action  of  the  fire.  The  deflection  at 
this  point  46  hrs.  after  the  load  had  been  applied  was  0.58  in. 
and  the  reading  after  the  load  had  been  removed  16  hrs.  was 
0.12  in. 


86 


Figure  45 

View  looking  west,  of  sample  used  in  Fire  and  Hose  Stream  Test 
before  test,  with  load  of  50  lbs.  per  sq.  ft.  applied.  Also  location  of 
interior  and  furnace  thermocouples  connected  to  junction  box  and 
deflection  targets  in  position. 


Figure  46 

View  looking  west  showing  excess  load  125  lbs.  per  sq.  ft.  (2^/i 
times  safe  rated  load)  after  being  subjected  to  standard  fire  condi- 
tions for  45  min.  and  then  a hose  stream  of  30  lbs.  per  sq. 

in.  was  applied  for  5 min. 


87 


Figure  47 

View  looking  west  showing  top  flooring  before  Fire  and  Hose 
Stream  Test,  after  Fire  and  Hose  Stream  Test  and  after  excess 
load  of  125  lbs.  per  sq.  ft.  was  removed. 


Figure  48 

View  looking  west  showing  furring  strips  and  deadening  felt  after 
finished  floor  was  removed  after  Fire  and 
Hose  Stream  Test 

88 


Figure  49 

View  looking  south,  showing  top  surface  of  rough  flooring  in  the 
damaged  area,  after  Fire  and  Hose  Stream  Test. 


Figure  50 

View  looking  south,  showing  underside  of  rough  flooring  in  the 
damaged  area  after  Fire  and  Water  Test.  Boards  turned  over  in 
the  same  relative  position  showing  damaged  area  and  smoke  stains. 

89 


Figure  51 

View  looking  south,  showing  joist  and  bridging  in  the  damaged  area 
after  Fire  and  Hose  Stream  Test,  rough  flooring  removed. 


Figure  52 

View  from  above,  showing  condition  of  joist  bridging  and  metal  lath 
and  cement  plaster  finish  in  the  damaged  area. 

90 


Figure  53 

View  from  above,  looking  into  joist  bays  showing  condition  of  joist 
bridging  metal  lath  and  portland  cement  finish  in  north  undam- 
aged section  of  floor  after  Fire  and  Hose  Stream  Test. 


Figure  54 

View  looking  west  and  upwards,  showing  condition  of  north  section 
of  metal  lath  and  portand  cement  plaster  finish  after  Fire  and 
Hose  Stream  Test,  west  walls  removed.  The  mottled  effect  is  from 
the  moisture  due  to  the  Hose  Stream  Test. 


1)1 


Figure  55 

View  looking  west  showing  the  condition  of  the  south  or  damaged 
area  of  the  metal  lath  and  Portland  cement  finish  after  the 
Fire  and  Hose  Stream  Test,  west  wall  removed. 


Figure  56 

View  showing  condition  of  deadening  felt  immediately  above  the 
damaged  area  in  the  rough  flooring  after  Fire  and 
Hose  Stream  Test 

92 


EXCESS  LOAD  TEST 


Observations  during  and  after  the  test  indicate  that  the  va- 
rious units  and  fastenings  possess  sufficient  strength  to  with- 
stand a live  load  of  125  lbs.  per  sq.  ft.  which  is  two  and  one- 
half  times  the  safe  rated  load  for  floors  of  this  class  without 
deflecting  at  the  middle  sufficient  to  cause  any  marked  open- 
ing in  the  small  cracks  which  were  formed  in  the  ceiling  finish 
during  the  Fire  and  Hose  Stream  Test.  The  results  show  the 
specified  factor  of  safety  in  strength  of  the  wood  joisted  floor 
construction  finish  with  metal  lath  and  portland  cement  plaster 
under  a normal  live  load  of  50  lbs.  per  sq.  ft. 


93 


APPENDIX  II 

TRANSVERSE  LOAD  TESTS  ON  METAL  LATH  AND 
GYPSUM  PLASTER  CONSTRUCTION: 
DESCRIPTION  OF  SAMPLES 

Two  test  panels,  each  having  a plastered  area  36  in.  by  50 
in.,  were  employed  in  these  tests.  Each  panel  comprised  a 
rectangular  framework  of  wood  members,  serving  as  a support 
for  wire  lath  and  gypsum  plaster. 

Each  panel  was  made  up  of  four  studs,  nominally  2 by  6 in., 
approximately  42^  in.  long,  spaced  16  in.  center  to  center,  with 
one  2 by  6 in.  piece,  50  in.  long,  nailed  across  each  end  of  the 
row  of  studs  and  preserving  their  relative  positions. 

One  face  of  the  framework  formed  by  the  studs  carried  2 
sheets  of  No.  26  U.  S.  gauge  diamond-mesh  wire  lath,  50  in.  long, 
one  sheet  being  20  in.  wide  and  the  other  14  in.,  lapped  2 in. 
to  provide  a total  with  of  36  in.  The  metal  lath  was  attached 
to  the  studs  by  No.  14  B.  W.  G.  (.083-in.)  staples,  spaced  4 to 
43^  in.  At  the  lapped  portion  the  two  sheets  were  secured  to- 
gether by  No.  18  B.  W.  G.  (.049-in.)  galvanized  steel  tie  wire. 

The  plaster  was  3-coat  work,  applied  with  ^-in.  grounds. 
The  scratch  coat  was  a mixture  of  1 part  Imperial  plaster  and 
one  part  sand  by  volume;  the  brown  coat  was  a 1 to  2 mixture. 
The  brown  coat  was  applied  about  48  hrs.  after  the  scratch  coat; 
the  finish  coat  about  72  hrs.  after  the  brown  coat. 

The  panels  were  7^4  months  old  when  tested. 

METHOD 

Each  panel  was  tested  separately  in  the  Laboratories’ 
10,000-lb.  Olsen  testing  machine,  which  was  provided  with 
special  attachments  for  transmitting  load  to  the  sample  and 
for  indicating  deflections. 

Each  panel  was  mounted  in  a horizontal  position  with  its 
plastered  surface  uppermost  and  was  loaded  by  means  of  a 
bar  in  contact  with  the  center  line  of  the  panel,  and  therefore 
midway  between  two  studs.  Load  was  applied  by  increments 
of  50  lbs.  and  all  results  were  noted. 

RESULTS 
Panel  No.  1 

Observations  During  Test — During  the  application  of  the 
load  the  finish  deflected  gradually  to  a maximum  of  about  34  in. 
at  1,000  lbs.  Rather  rapid  deformation  at  this  time  caused  the 
load  to  decrease  to  about  800  lbs.  Continual  increase  in  the 
load  to  a maximum  of  1,200  lbs.  caused  a deflection  of  about 
^ in.  Continual  operation  of  the  testing  machine  resulted  in 
the  rapid  increase  of  deflection  to  about  3 in.  with  continually 
diminishing  load. 


94 


TRANSVERSE  LOAD  TESTS 


Slight  cracking  near  the  middle  of  the  panel  occurred  at 
loads  of  about  600  and  700  lbs.  At  1,000  lbs.  large  cracks  de- 
veloped along  the  line  of  application  of  the  load  and  above  each 
inner  stud. 

Condition  After  Test — Large  cracks  extending  the  entire 
width  of  the  panel  were  formed  along  the  line  of  application  of 
the  load  and  over  each  of  the  two  inner  studs.  The  lath  was 
ruptured  along  an  irregular  line  following  the  general  direc- 
tion of  the  loading  line,  the  mesh  having  elongated  consider- 
ably before  failure.  The  brown  and  scratch  coats  could  be 
easily  separated  everywhere  in  the  middle  third  of  the  panel. 

Panel  No.  2 

Observations  During  the  Test — During  the  application  of 
the  load  the  finish  deflected  gradually  to  a maximum  of  about 
0.10  in.  at  850  lbs.  Rather  rapid  deformation  at  this  time  caused 
the  load  to  decrease  to  about  800  lbs.  Continued  increase  in 
the  load  to  a maximum  of  1250  lbs.  caused  a deflection  of 
about  Yz  in.  Continued  operation  of  the  testing  machine  re- 
sulted in  the  rapid  increase  of  the  deflection  to  about  2^/2  in., 
with  continually  diminishing  load. 

No  apparent  cracking  occurred  at  loads  less  than  850  lbs. 
Under  this  load  large  cracks  developed  along  the  line  of  appli- 
cation of  the  load  and  above  each  inner  stud. 

CONDITION  AFTER  TEST 

The  condition  of  the  sample  was  similar  to  that  reported 
for  Panel  No.  1. 


95 


APPENDIX  III 
SPECIFICATIONS 

for 

PREPARATION  AND  INSTALLATION 

of 

METAL  LATH  AND  SANDED  AND  WOOD  FIBERED 
GYPSUM  PLASTER  CONSTRUCTION 

on 

WOOD  SUPPORTS 

The  material  for  the  studs,  sills,  plates  and  supports  is 
usually  shipped  to  the  job  in  random  lengths.  The  metal  lath 
is  furnished  in  bundles,  the  staples  in  packages  or  kegs,  the 
wire  in-  coils,  the  spot  grounds  in  boxes,  the  metal  corner  bead- 
ing in  bundles,  the  plaster  in  bags  and  the  sand  in  bulk.  The 
frames,  doors,  sash  and  some  of  the  standing  finish  are  as- 
sembled at  the  mill  and  delivered  to  the  job  in  separate  units 
braced  to  prevent  injury  in  handling.  The  running  trim  is 
often  delivered  in  random  lengths. 

Installation  of  Studs,  Trusses  and  Fire  Stops — The  studs 
are  usually  installed  after  the  floor  joists  and  rough  flooring  are 
in  place.  They  are  cut  to  length,  the  sills  and  plates  nailed 
in  place  and  erected  in  position  as  shown  by  the  plans.  They 
are  then  set  plumb  and  true  to  the  line  and  held  in  position  by 
temporary  bracing  until  the  next  floor  joists  are  in  position  on 
the  plates,  the  joists  being  well  spiked  to  the  plates.  The 
trusses  are  then  installed  over  the  openings,  and  the  grounds 
nailed  to  the  rough  framing  around  the  openings.  The  fire 
stops  are  securely  attached  in  proper  position  between  the  studs 
and  other  details  of  the  partition  framing  completed. 

Application  of  Lath — The  lath  is  installed  after  the  building 
is  closed  in.  The  sheets  of  lath  are  attached  to  the  studs  in 
horizontal  courses  beginning  at  the  top.  The  upper  sheets  are 
bent  so  that  they  lap  the  ceiling  joiilt  at  least  6 in.  to  reinforce 
the  corners  and  prevent  cracking  in  the  plaster.  Each  suc- 
cessive course  is  laid  so  that  its  upper  edge  overlaps  the  lower 
edge  of  the  preceding  course  at  least  ^ in.  so  as  to  present  no 
obstruction  to  the  plastering  trowel.  The  edges  at  the  ends 
of  the  sheets  are  also  overlapped  at  least  1^  in.  and  the  sheets 
bent  so  that  they  overlap  adjoining  surfaces  at  least  4 in.  at 
the  angles  with  walls  and  partitions.  The  vertical  joints  be- 
tween the  sheets  are  broken  at  each  course.  The  lath  is  cut 
close  up  to  the  grounds  at  the  floor  and  framing  at  the  open- 
ings. It  is  attached  to  each  stud  to  which  it  is  secured  by  1^  in. 
staples  or  by  l^^  in.  nails  driven  partly  in  and  bent  over  and 
spaced  not  exceeding  8 in. 


96 


METAL  LATH  AND  PLASTER  CONSTRUCTION 


Metal  lath  is  attached  to  ceiling  supports  by  not  less  than 
6-penny,  2-in.  nails  driven  partly  in  and  bent  over  and  spaced 
at  not  exceeding  6 in.  centers,  'when  the  supports  are  spaced 
at  not  exceeding  16  centers.  Metal  lath  for  interior  walls 
and  partitions  should  'weigh  not  less  than  2.5  lbs.  per  sq.  yd. 
or  26  U.  S.  gauge  steel  and  for  ceilings  not  less  than  3.0  lbs. 
per  sq.  yd.  or  25  U.  S.  gauge  steel.  The  metal  lath  to  be  of 
the  expanded  diamond  mesh  patterns.  The  overlapping  edges 
of  the  sheets  are  tied  'with  No.  18  gauge  annealed  tie  'wire  mid- 
■way  between  supports. 

Where  large  coves  are  provided  at  the  junctions  between 
partitions  and  ceilings,  the  metal  framing  is  first  securely  nailed 
to  the  studs  and  joists.  The  lath  is  then  attached  to  the  fur- 
ring by  tie  wire  so  as  to  form  the  curved  base  for  the  plaster. 
Small  coves  are  usually  formed  of  solid  plaster  formed  to 
the  desired  design. 

The  metal  corner  beading  is  nailed  to  the  supports  at  the 
outside  angles  of  the  walls  and  partitions. 

Preparation  of  Sanded  Gypsum  Plaster — The  gypsum  plas- 
ter is  stored  in  a clean,  dry  place  until  used  and  is  mixed  in 
batches  that  can  be  used  within  one  hour  after  mixing.  The 
proper  proportions  of  sand  and  plaster  are  obtained  by  any  con- 
venient method  of  accurately  measuring  these  materials.  Only 
clean  water  free  from  alkali  and  impurities  is  used.  The  mix- 
ing box,  mortar  boards  and  tools  are  kept  well  cleaned,  to  pre- 
vent the  mixing  of  one  gauging  of  plaster  with  another.  The 
plaster  to  consist  of  two  parts  by  weight  of  clean,  dry,  sharp 
sand  to  one  of  neat  gypsum  plaster.  Hair  or  plastering  fiber 
to  be  added  as  desired  for  the  coat. 

The  plasters  for  the  scratch  and  brown  coats  are  mixed 
by  placing  a layer  of  sand  in  the  mixing  box  and  then  a 
layer  of  plaster  in  the  proportions  specified,  and  mixed  dry. 
Water  is  then  added  and  the  dry  mixture  hoed  back  and  mixed 
into  the  water  until  a thin  plaster  of  uniform  consistency  and 
appearance  is  secured.  Sufficient  dry  plaster  and  sand  in  the 
proper  proportions  are  added  and  thoroughly  mixed  in  until 
the  plaster  is  of  the  proper  consistency  for  application.  The 
plaster  is  never  retempered  and  used  after  it  has  commenced 
to  set. 

The  lime  putty  finish  is  usually  mixed  on  a mortar  board, 
using  a lime  putty  made  from  thoroughly  slacked  quick  lime 
or  hydrated  lime  mixed  with  water  and  allowed  to  stand  for 
about  24  hours.  A ring  of  lime  putty  about  2 ft.  in  diameter 
and  6 in.  high  is  first  formed  on  the  mortar  board,  about  4 in. 
of  water  is  poured  into  the  ring  and  the  dry  calcined  gypsum 
then  sifted  into  the  water  in  the  proper  proportion.  After  the 


97 


APPENDIX  III— SPECIFICATIONS 


gypsum  plaster  has  soaked  for  a few  minutes  it  is  mixed  with 
the  lime  putty  to  a uniform  paste  ready  for  application. 

Application  of  Plaster  Coatings — The  scratch  coat  of  plaster 
is  applied  lightly,  but  with  sufficient  pressure  to  embed  the 
lath  in  the  plaster  and  thoroughly  cover  the  lath  on  the  finish 
side.  The  surface  of  this  coat  is  well  scratched  in  both  direc- 
tions to  provide  a bond  for  the  brown  coat. 

After  the  scratch  coat  has  set  firm  and  hard,  but  while  it 
is  still  green,  the  spot  grounds  and  the  brown  coat  are  ap- 
plied. The  grounds  are  first  attached  to  the  surface  of  the 
scratch  coat  with  a neat  gypsum  plaster.  They  are  set  to  a 
line  so  that  their  outer  faces  are  % in.  out  from  the  supports 
and  so  that  they  are  in  proper  position  back  of  the  points  where 
the  standing  finish  is  to  be  applied.  A skin  coat  of  plaster  is 
then  applied  to  the  scratch  coat  and  sufficient  additional  plaster 
immediately  spread  on  to  bring  the  brown  coat  out  practically 
flush  with  the  grounds.  The  surface  is  made  straight  and  true 
with  a rod  and  darby. 

After  the  brown  coat  has  dried  out,  the  finish  coat  is  ap- 
plied. If  the  suction  is  too  great,  the  brown  coat  is  first  sprin- 
kled with  clean  water  with  a clean  brush.  Enough  material 
to  cover  the  surface  completely  is  first  applied  and  worked 
thoroughly  into  the  brown  coat,  using  the  material  as  thin  as 
possible.  This  coating  is  allowed  to  draw  for  a few  minutes 
to  avoid  blistering  and  enough  material  then  applied  to  make 
the  surfaces  perfectly  true.  The  surface  is  then  gone  over  a 
third  time  with  the  material  as  thin  as  it  can  be  handled  and 
all  imperfections  worked  out.  After  this  coating  has  drawn 
for  a few  minutes,  it  is  troweled  to  a smooth  surface,  applying 
water  with  a brush  as  necessary.  The  top  and  bottom  of  the 
walls  are  worked  at  the  same  time  to  avoid  joining. 

During  hot  weather,  the  openings  into  the  building  are 
closed  to  prevent  drafts  of  hot  winds  from  drying  out  the 
plaster  before  it  properly  sets  or  crystalizes.  If  white  or 
chalky  spots  appear  they  are  sprinkled  with  clear  water  with 
a clean  brush  until  the  material  sets  up  and  hardens.  The 
windows  are  then  opened  and  a free  circulation  of  air  per- 
mitted after  the  plaster  has  set. 

During  freezing  weather,  the  building  is  heated  to  keep 
the  plaster  from  freezing  until  it  has  set  and  become  hard, 
after  which  a free  circulation  of  air  is  permitted  so  that  the 
plaster  will  dry  out  quickly. 

During  damp  or  rainy  weather,  the  building  is  heated  to 
facilitate  drying  after  the  plaster  has  set  and  become  hard. 


98 


METAL  LATH  AND  PLASTER  CONSTRUCTION 


After  the  plaster  coatings  have  become  thoroughly  dry,  the 
standing  finish  is  attached  by  nailing  through  into  the  grounds, 
and  the  doors  and  sash  mounted  in  position  in  the  openings  in 
the  usual  manner. 

Wood-Fibered  Gypsum  Plaster — Wood-fibered  gypsum  plas- 
ter is  prepared  and  applied  similar  to  sanded  gypsum  plaster, 
except  that  no  sand  or  hair  is  used  in  the  preparation  of  the 
finish.  This  finish  is  prepared  ready  for  mixing  with  the  de- 
sired quantity  of  water. 


APPENDIX  IV 

CLAIMS  MADE  BY  THE  SUBMITTORS 

The  Submittors  set  forth  the  following  statemehts  relative 
to  this  interior  construction : 

PRINCIPLE  OF  DESIGN: 

Expanded  metal  lath  is  a fabric  made  from  sheet  metal  so 
expanded  as  to  form  a support  or  vehicle  on  which  plastic 
materials  can  be  applied  and  held  in  place  until  set.  There- 
after it  provides  a perfect,  permanent  mechanical  key  and  re- 
inforces the  plaster  coat  against  cracking  or  falling.  It  ef- 
fectively holds  the  plaster  in  position  after  deterioration  by 
fire  so  that  the  insulating  value  of  the  plaster  is  maintained 
long  after  it  would  otherwise  have  dropped  ofif  or  become  use- 
less. It  is  incombustible  in  itself  and  will  not  shrink,  swell 
nor  warp. 

It  is  cut  from  sheets  of  steel  of  standard  known  thickness, 
with  a determined  width  of  strand  and  fabricated  by  machine 
to  a determined  size  of  mesh.  It  is  provided  with  a protective 
coating  of  sufficient  durability  to  protect  it  from  the  weather 
before  application. 

The  wood  studs  or  joists  are  manufactured  at  the  saw  mill 
into  standard  lengths  and  commercial  sections.  They  are 
placed  on  end  with  the  long  axis  of  the  section  across  the 
partition  braced  in  the  middle  to  reduce  the  length  of  the 
free  column.  Practically  no  shrinkage  takes  place  in  the  direc- 
tion of  the  grain. 

The  plastic  material  is  prepared  in  such  a manner  that 
it  may  be  mixed  with  sand  and  water  at  the  job  for  ready  ap- 
plication with  a trowel.  Fiber  is  added  to  the  first  coat  to  hold 
the  keys  in  position  until  they  set.  The  studs  or  joists  are 
erected  12  in.  or  16  in.  on  centers,  lath  stapled  or  nailed  in 
position,  and  the  plaster  applied  to  form  monolithic  protective 
coating  without  disfiguring  joints  or  the  necessity  of  unsightly 
battens.  No  nails  are  exposed  to  view. 

FIRE  STOPS: 

Fire  stops  at  floor  levels  are  provided  by  the  use  of  a metal 
lath  basket  filled  with  incombustible  materials  and  fully  occu- 
pying the  space  between  joists  and  studs  to  a height  of  4 in. 
above  floor  level  or  other  fire  stops  approved  by  the  Building 
Code  of  the  National  Board  of  Fire  Underwriters.  -The  brace 
between  the  studs  midway  between  floor  and  ceiling  also  acts 
as  a fire  stop. 

PRACTICABILITY: 

The  metal  lath  is  easily  cut,  lapped  and  fitted  and  can  read- 
ily be  'made  to  conform  to  plane  or  irregular  surfaces.  Expos- 


100 


FIRE  RETARDANCE  AND  DURABILITY 


ure  to  weather  or  rough  usage  during  shipment  is  of  little  con- 
sequence to  the  metal  lath  or  lumber.  The  plastic  material 
must  be  protected  from  moisture. 

The  only  tools  needed  for  the  application  of  metal  lath  are 
snips,  pliers  and  a lather’s  hatchet.  Wood  studs  need  only  a 
saw  and  hammer  and  the  plastic  materials,  a hoe,  trowel  and 
straight  edge. 

The  metal  lath  does  not  contribute  to  ruining  of  the  dec- 
orations by  staining  nor  by  creating  zones  of  different  tempera- 
tures, the  colder  of  which  cause  condensation  on  which  dust 
settles. 

This  combination  of  materials  is  entirely  practical  and  per- 
mits the  construction  of  very  strong  and  light,  bearing  and  non- 
bearing partitions.  They  are  easily  made  straight  and  true. 
The  metal  lath  demands  a thick  covering  of  plaster  in  three 
coats  and  does  not  lend  itself  to  skimping,  or  amateur  work- 
manship. It  permits  the  application  of  plaster  in  sufficient 
thickness  to  form  a practically  sound-proof  partition.  The 
insulating  material  and  the  thickness  of  the  plaster  render  the 
floor  more  sound  proof  than  ordinary  combinations. 

Wood  joisted  floor  construction  is  the  most  universally  used 
floor  construction  in  America  today.  Its  overwhelming  per- 
centage of  use  proves  it  to  be  not  only  economical  but  familiar 
to  all  mechanics  in  the  building  trades. 

BEARING  CAPACITY: 

The  metal  lath  being  tightly  stapled  or  nailed  to  the  wood 
supports  gives  them 'additional  bracing  in  all  directions  in  the 
plane  of  the  partition  and  forms  the  diagonal  members  of  a 
very  deep  and  strong  truss.  This  is  effective  even  after  the 
plaster  has  disintegrated.  This  truss  may  be  very  valuable  in 
preventing  the  collapse  of  floors  attached  to  or  supported  by  it. 
The  metal  lath  effectively  prevents  - the  studs  from  buckling 
in  the  direction  of  their  shortest  axis  and  makes  a wood. stud 
partition  extremely  rigid. 

Weights  supported  by  individual  studs  may  be  transferred 
by  the  metal  lath  to  other  studs;  consequently,  the  loss  of  con- 
siderable areas  of  plaster  can  be  suffered  without  rendering  the 
partition  incapable  of  performing  its  structural  function. 

Joisted  construction  for  plastering  is  always  designed  with 
the  maximum  allowable  bending  as  the  criterion ; consequently 
there  is  always  a strength  greater  than  necessary  for  the  mere 
support  of  the  designed  load,  and  the  lower  side  of  the  joists 
can  suffer  severe  charring  and  even  burning  before  they  become 
inadequate  to  carry  the  load.  Even  though  sagging  should 
take  place,  the  expanded  metal  lath  will  conform  to  the  sag 


101 


APPENDIX  IV— SUBMITTORS’  CLAIMS 


and  the  plaster  will  not  drop  off,  due  to  elongation  in  the 
lower  fibres. 

No  appreciable  loss  in  load  carrying  capacity  is  experienced 
under  fire  conditions  while  the  metal  lath  and  plaster  remains 
intact,  and  continues  to  insulate  the  wood  from  heat.  The  first 
appearance  of  disintegration  is  charring,  which  progresses  at  a 
slow  rate. 

The  penetration  of  fire  at  one  locality  or  the  loss  of  sec- 
tional area  in  several  adjacent  joists  does  not  limit  the  bearing 
capacity  of  this  floor  system,  nor  immediately  destroy  its  load 
bearing  value. 

RETARDATION: 

The  great  virtue  of  this  combination  of  materials  in  fire  re- 
tardation is  the  ability  of  metal  lath  to  lengthen  the  retarding 
value  of  any  plastic  coating  that  may  be  put  upon  it,  by  hold- 
ing the  coating  in  place  even  after  it  has  been  reduced  in 
strength  by  the  action  of  heat,  and  so  reinforcing  it  to  prevent 
cracks  from  developing,  thereby  gaining  the  maximum  insulat- 
ing value  before  any  flame  can  pass. 

The  metal  lath  and  plaster  provide  no  combustible  material 
to  add  fuel  to  the  fire  within  hollow  spaces.  The  metal  lath 
generates  no  gases  or  develops  no  other  deleterious  properties 
which  may  tend  to  break  the  bond  or  key  and  throw  off  the 
plaster  coating.  The  three  most  common  plastic  coats,  port- 
land  cement,  gypsum  and  lime,  or  combinations  of  them,  are  in- 
combustible and  heat  insulating.  The  wood  studs  are  com- 
bustible, but  being  protected  by  the  plastic  coating  from  heat 
and  fire,  will  maintain  sufficient  cross  section  to  continue  their 
function,  as  a bearing  partition,  safely  for  long  periods  and 
under  all  conditions  of  fire  exposure  likely  to  occur  in  premises 
for  which  this  construction  is  advocated. 

FUNCTION  AS  FIRE  BARRIER: 

Its  function  as  a fire  barrier  is  not  measured  solely  by  the 
period  in  which  fire  may  destroy  the  exposed  face,  since  the 
studs  and  other  face  must  still  be  destroyed. 

In  wood  joist  floor  construction  its  function  as  a fire  barrier 
is  limited  to  its  ability  to  carry  the  actual  live  load  existing, 
and  will  thus  retain  its  integrity  as  a fire  barrier  even  after  the 
joists  themselves  have  been  continuing  to  burn  and  until  fire 
actually  penetrates  the  upper  flooring. 

DURABILITY: 

The  metal  lath  resists  all  physical  damage  to  the  plaster  by 
virtue  of  its  reinforcement  and  being  manufactured  of  steel  it 
has  great  strength  and  durability.  It  is  easy  to  repair  by  wir- 


102 


SAFE  BEARING  STRENGTH 


ing  on  additional  material  if  the  mesh  is  broken  or  by  ap- 
plication of  more  plaster  if  the  coating  only  is’  broken.  It  is 
not  subject  to  progressive  corrosion  under  ordinary  condi- 
tions of  habitable  buildings.  It  is  protected  by  its  ov^n  coat- 
ing and  further  protected  by  its  encasement  in  any  one  of  the 
common  plastering  materials.  This  partition  resists  vibration 
and  cracking  from  sudden  shocks,  is  vermin  and  rodent  proof. 
It  is  one  that  cannot  ordinarily  be  punctured  by  rough  occu- 
pancy, but  can  be  easily  cut  for  alterations  when  desired.  If 
desired,  it  can  be  patched  in  a sightly  manner,  mechanically 
right.  ... 

This  combination  of  materials  forms  a partition  of  great 
lateral  strength,  calling  into  play  the  resistance  of  the  wood 
studs  or  joist  as  well  as  the  metal  lath  and  plaster.  The  par- 
tition also  has  a great  resistance  to  being  punctured  by  falling 
objects  and  absorbs  impact  of  falling  objects  or  concussion  of 
explosions.  It  is  resilient  and  not  brittle  and  can  be  depended 
upon  to  resist  successfully  many  conditions  of  fire  hazard.  If 
dislodged  it  does  not  break  up  into  its  constituent  parts,  but 
may  fall  intact  as  a blanket  to  retard  fire  even  after  it  has  lost 
its  original  position. 

ECONOMIES: 

The  economy  of  this  construction  is  improved  by  continuing 
popularity  of  thirty  years. 

Numerous  examples  of  this  type  of  partition  can  be  found 
with  satisfactory  service  records  for  thirty  years  or  more. 

STR^GTH  AS  BEARING  PARTITIONS 

This  combination  of  materials  is  entitled  to  recognition  as 
an  interior  bearing  partition  or  wall  under  any  condition  of 
safe  loading  for  any  wood.  The  following  examples  are  sub- 
mitted : 

Live  load  assumed  at  50  lbs.  per  sq.  ft. 

Ceiling  height,  11  ft. 

When  2 by  4 in.  studs  are  used,  16  in.  center  to  center,  this 
partition  will  safely  carry  a structure  consisting  of  two  sup- 
ported floors,  each  with  a span  of  12  ft.  on  both  sides  of  the 
partition,  or  the  equivalent  thereof.  Additional  load  of  33  per- 
cent for  12  in.  C.  C. 

When  2 by  4 in.  studs  are  used,  16  in.  center  to  center,  this 
partition  will  safely  carry  a . structure  consisting  of  one  floor, 
with  two  20  ft.  spans  on  each  side  of  the  partition,  or  the  equiva- 
lent thereof.  Additional  load  of  33  per  cent  for  12  in.  C.  C. 

When  2 by  4 in.  studs  are  used,  12  in.  center  to  center,  this 
partition  will  safely  carry  a structure  consisting  of  two  sup- 
ported floors,  each  with  a span  of  16  ft.  on  both  sides  of  the 
partition,  or  the  equivalent  thereof. 


103 


APPENDIX  IV— SUBMITTORS’  CLAIMS 


When  2 by  6 in.  studs  are  used,  16  in.  center  to  center,  this 
partition  will  safely  carry  a structure  consisting  of  two  sup- 
ported floors,  each  with  a span  of  20  ft.  on  both  sides  of  the 
partition,  or  the  equivalent  thereof.  Additional  load  of  33  per 
cent  for  12  in.  C.  C.. 

When  2 by  6 in.  studs  are  used,  16  in.  center  to  center,  this 
partition  will  safely  carry  a structure  consisting  of  three  sup- 
ported floors,  each  with  a span  of  18  ft.  on  both  sides  of  the 
partition,  or  the  equivalent  thereof.  Additional  load  of  33  per 
cent  for  12  in.  C.  C. 

The  above  conditions  of  loading  are  all  safe,  in  accordance 
with  customary  engineering  design  and  practice,  allowing  an 
ample  factor  of  safety. 

NON-BEARING  PARTITIONS: 

This  partition  will  effectively  act  as  a non  bearing  fire  bar- 
rier, with  2 by  2 in.  or  larger  studs,  under  an}^  conditions  of 
fire  hazard  for  at  least  one  hour.  In  buildings  of  so-called  fire- 
proof construction,  it  may  be  used  under  any  conditions  in 
which  a partition  is  required. 

SAFETY  AFTER  CHARRING: 

Calculations  show  that  79  per  cent  of  the  strength  of  the 
partition  will  still  remain  when  the  faces  of  all  2 by  4 in.  studs 
are  charred  to  an  average  depth  of  Yi  in.  A factor  of  safety 
of  3.6  will  then  remain. 

The  charring  on  2 by  4 in.  studs  may  average  a depth  of 
1 in.  and  even  then  retain  52  per  cent  of  the  strength  of  the 
partition,  or  a factor  of  safety  2.1. 

On  the  2 by  6 in.  studs,  77  per  cent  of  the  original  strength 
of  the  partition  will  be  retained  after  the  charring  has  gone  to 
a depth  of  1 in.  A factor  of  safety  3.08  will  still  remain. 

On  account  of  the  fact  that  wood  joisted  floors  with  plaster 
finish  are  designed  with  the  maximum  deflection  of  1/360  of 
the  span  as  the  criterion,  and  as  this  produces  a stronger  floor 
than  if  the  joists  be  designed  for  strength  alone,  there  is  an 
excess  of  stability  which  will  permit  of  considerable  charring  or 
actual  burning  before  failure  occurs. 

EFFECT  OF  HOSE  STREAMS: 

While  there  is  sufficient  fire  retarding  value  in  the  plaster 
coat  to  permit  the  studs  to  retain  ample  strength  against  col- 
lapse for  a considerable  period  without  the  aid  of  fire  depart- 
ment or  other  fire  quenching  apparatus,  it  should  be  recog- 


104 


MINIMUM  AND  ALTERNATE  SPECIFICATIONS 


nized  that  the  assistance  of  such  apparatus  will  reduce  the 
length  of  exposure  in  buildings. 

Unless  the  fire  department  is  present  in  such  strength  as 
to  gain  control  of  the  fire,  water  could  not  be  applied  with  suf- 
ficient force  to  throw  off  sections  of  plaster  large  enough  to 
expose  bearing  members  to  complete  collapse.  This  is  due  in 
partitions  to  the  truss  action  set  up  if  several  studs  are  com- 
pletely burned  through,  transferring  the  loads  to  all  other  studs, 
and  in  floor  construction,  to  the  fact  that  the  floor  is  bridged 
frequently  and  that  the  double  flooring  acts  as  a fire  retardant 
and  is  strong  enough  to  span  over  four  or  five  joists,  should 
they  completely  disappear. 


IU5 


APPENDIX  V 


UNDERWRITERS’  LABORATORIES’  STANDARD 
EQUIPMENT  AND  PANELS  FOR  TESTS  OF  IN- 
TERIOR  WALL,  AND  PARTITION  FINISH  ON 
WOOD  SUPPORTS. 

GENERAL  CHARACTER: 

The  equipment  for  the  tests  of  partitions  consists  of  the 
apparatus  used  for  the  Fire  and  Stream  Tests  and  the  apparatus 
for  the  tests  of  materials. 

The  standard  test  panels  consist  of  at  least  one  panel  of 
standard  size  for  each  of  the  tests,  made  of  the  materials  under 
investigation  and  seasoned  until  in  normal  condition. 

The  equipment,  with  the  exception  of  some  of  the  apparatus 
used  in  the  tests  of  materials,  is  located  in  a building  of  fire 
resistive  construction  specially  designed  for  work  of  this  char- 
acter and  known  as  building  No.  3.  The  building  is  heated 
during  cold  weather  and  the  tests  are  not  unduly  subject  to  out- 
side weather  influences. 

FIRE  AND  HOSE  STREAM  TESTS 

The  equipment  used  in  these  tests  consists  of  the  apparatus 
for  handling  the  test  panels,  the  furnace  in  which  the  test  panels 
are  subjected  to  fire,  the  apparatus  for  measuring  the  tempera- 
tures in  the  furnace  and  the  transmission  of  heat  through  the 
panels,  the  apparatus-  for  measuring  the  deflections  of  the 
panels,  the  gauge  for  measuring  the  fire  pressures  in  the  furnace, 
and  the  hydrant  and  nozzle  by  means  of  which  the  stream  of 
water  is  applied  in  the  Fire  Stream  Tests.  The  equipment  is 
located  in  the  first  story  of  the  building. 

STANDARD  TEST  PANELS: 

The  standard  test  panels  are  10  ft.  wide  and  11  ft.  high,  and 
consist  of  a standard  frame  of  wood  studs  covered  on  one  or  both 
sides  with  the  materials  under  investigation,  installed  as  nearly 
as  possible  in  the  manner  advocated  by  the  *Submittor.  The 
panels  are  mounted  in  the  openings  in  the  movable  walls  forming 
the  front  of  the  test  furnace. 

The  standard  frame  consists  of  eight  2 by  4-in.‘ yellow  pine 
studs  spaced  on  16-in.  centers  except  at  the  sides  where  they 
are  spaced  4 in.  so  as  to  completely  fill  the  10-ft.  wall  opening. 
The  studs  are  nailed  to  single  2 by  4-in.  yellow  pine  plates  and 
sills  extending  across  the  top  and  bottom,  respectively.  The 
side  studs  are  nailed  to  wooden  inserts  set  in  the  side  walls  at 
24-in.  intervals,  and  the  frame  is  made  tight  against  the  masonry 
at  all  points  with  mortar. 


106 


EQUIPMENT  EOR  WALL  TESTS 


APPARATUS  FOR  HANDLING  TEST  PANELS: 

This  apparatus  consists  of  the  movable  walls  in  which  the 
test  panels  are  mounted,  a system  of  overhead  step  beams  from 
which  the  movable  walls  are  suspended,  a traveling  crane  by 
which  the  movable  walls  are  transferred  to  various  ceiling  beams, 
the  trolleys  by  which  the  movable  walls  are  conveyed  along  the 
ceiling  beams  to  the  traveling  crane  and  into  the  test  furnace, 
and  an  electric  hoist  by  which  the  movable  walls  are  drawn 
from  the  furnace  at  the  end  of  the  fire  tests. 

The  movable  walls  consist  of  heavy  steel  sections  assembled 
in  the  form  of  rectangles  and  the  masonry  necessary  to  protect 
the  steel  from  heat  during  the  tests  and  provide  openings  for 
the  standard  test  panels.  The  rectangular  steel  frames  are 
designed  to  carry  all  loads  and  resist  the  expansion  in  the  test 
panels  during  the  periods  they  are  exposed  to  fire.  Each  mov- 
able wall  is  provided  with  two  trolleys  attached  to  the  steel 
work  at  the  top. 

The  overhead  beams  are  attached  to  the  ceiling  on  each  side 
of  the  middle  bay  in  which  the  traveling  crane  moves.  One 
end  of  each  beam  registers  with  a similar  beam  at  the  bottom 
of  the  traveling  crane.  The  overhead  beams  provide  for  the 
handling  and  storage  of  fifteen  movable  walls  in  addition  to  one 
in  front  of  the  furnace  and  one  for  the  installation  of  a new  test 
panel. 

The  traveling  crane  is  specially  designed  to  handle  the  mov- 
able walls  in  which  the  test  panels  are  mounted.  It  is  operated 
from  the  oor  by  a hand  chain  and  serves  to  transfer  the  movable 
walls  between  the  storage  beams  and  the  test  furnace. 

The  trolleys  are  securely  but  loosely  attached  to  the  top 
of  the  movable  walls  and  travel  on  the  lower  flanges  of  the  over- 
head beams.  They  are  operated  from  the  floor  by  hand  chains 
and  serve  to  support  the  movable  walls  and  convey  them  to  and 
from  the  traveling  crane  and  into  position  in  front  of  the  test 
furnace. 

The  hoist  has  a capacity  of  four  tons,  is  provided  with  two 
drums  and  is  electrically  driven.  It  is  used  to  draw  the  remov- 
able walls  carrying  the  test  panels  from  the  furnace  at  the  end 
of  the  fire  tests,  a steel  cable  being  attached  to  the  steel  frame 
of  the  wall.  The  hoist  is  located  at  one  side  of  the  test  furnace 
on  the  second  story  of  the  building. 

STANDARD  TEST  FURNACE: 

The  furnace  employed  in  the  tests  of  partition  panels  is 
known  as  furnace  No.  2.  The  furnace  proper  consists  of  a 
shallow  combustion  chamber  approximately  12  ft.  wide,  14^  ft. 
high  and  16  in.  deep,  communicating  at  the  bottom  with  a pit 


107 


APPENDIX  V— UNDERWRITERS’  LABORATORIES 


about  3 ft.  in  depth.  The  combustion  chamber  is  enclosed  by  a 
solid  brick  wall  at  the  back  and  one  end,  and  by  movable  brick 
walls  in  steel  frames  at  the  front  and  the  other  end.  The  mov- 
able walls  are  suspended  from  overhead  steel  beams  by  trolleys, 
the  wall  forming  the  front  of  the  furnace  being  provided  with  an 
opening  of  the  size  of  the  panel  to  be  tested.  The  top  of  the 
furnace  consists  of  heavy  fire  clay  blocks  containing  six  vents 
leading  to  a stack.  The  vents  are  provided  with  dampers  made 
of  fire-resisting  material.  Each  end  wall  of  the  furnace  is  pro- 
vided with  four  observation  holes  glazed  with  mica  and  so 
arranged  that  all  parts  of  the  interior  of  the  combustion  chamber 
and  the  exposed  face  of  the  test  panel  may  be  observed.  Obser- 
vation galleries  outside  of  the  furnace  afford  access  to  the  upper 
observation  holes. 

The  furnace  is  heated  by  means  of  six  4-in.  blast  burners 
mounted  in  the  back  wall  of  the  furnace  at  the  bottom  of  the 
combustion  chamber.  The  burners  are  supplied  with  gas  and 
air  through  mixing  tubes  which  enter  the  furnace  at  the  back. 
Additional  air  is  supplied  directly  to  the  combustion  chamber 
through  fifty  secondary  air  inlets  uniformly  spaced  over  the 
back  wall  of  the  chamber.  The  flow  of  gas  and  air  to  each  burner 
and  to  each  secondary  air  inlet  is  regulated  by  individual  valves 
provided  with  graduated  scales  so  that  the  valve  settings  may 
be  duplicated  accurately. 

Gas  is  supplied  to  the  furnace  through  a 6-inch  pipe  connected 
directly  to  the  street  mains.  Air  is  supplied  to  the  burners  and 
to  the  secondary  air  inlets  by  a blower  driven  by  an  electric 
motor.  The  entire  gas  and  air  supplies  are  each  controlled  by 
valves  in  the  main  connections. 

The  apparatus  for  measuring  the  temperatures  within  the 
furnace  consists  of  five  thermo-couples  symmetrically 'distributed 
over  the  exposed  surface  of  the  test  panel,  the  instruments  for 
indicating  the  temperatures,  and  a switchboard  and  connections 
for  placing  any  of  the  thermo-couples  in  circuit  with  the  instru- 
ments. The  thermo-couples  are  inserted  through  openings  in 
the  back  wall  of  the  furnace  and  located  6 in.  from  the  face  of  the 
test  panel.  The  connections  are  such  that  the  position  of  the 
couples  can  be  maintained  in  case  of  deflections  in  the  test  panel. 
Mercury  thermometers  are  suspended  near  the  cold  junctions  of 
the  thermo-couples  for  use  in  ascertaining  the  corrections  to 
be  made  in  the  temperature  readings. 

APPARATUS  FOR  TEMPERATURE  MEASURE- 
MENTS: 

The  apparatus  for  measuring  the  temperatures  on  the  unex- 
posed face  of  the  test  panel  consists  of  five  mercury  thermom- 


108 


EQUIPMENT  FOR  WALL  TESTS 


eters  symmetrically  distributed  over  the  surface  of  the  test  panel 
opposite  the  thermo-couples  in  the  furnace.  The  bulbs  are  in 
contact  with  the  surfaces  of  the  test  panel  and  are  protected 
from  outside  influences  by  uniform  plaster  of  Paris  shields 
cemented  to  the  surface  of  the  test  panel.  The  temperatures 
are  read  directly  or  by  a telescope  mounted  at  a convenient 
distance  back  of  and  opposite  the  middle  of  the  test  panel. 

APPARATUS  FOR  DEFLECTION  MEASUREMENTS: 

The  apparatus  for  measuring  deflections  on  the  unexposed 
face  of  the  test  panels  during  the  fire  tests  consists  of  three 
wires  stretched  horizontally  across  the  face  of  the  panel  and 
firmly  attached  to  the  channels.  The  wires  are  symmetrically 
spaced,  one  being  at  the  middle  and' one  half  way  between  on 
either  side  of  the  middle  wire.  The  position  of  the  sample  with 
respect  to  the  wires  is  noted  at  the  middle  of  the  top  and  bottom 
wires  and  at  three  points  on  the  middle  wire,  the  points  being 
symmetrically  located  from  the  middle  of  the  panel  and  occu- 
pying the  same  relative  position  in  each  case.  The  readings  are 
taken  from  a platform  'constructed  in  front  of  the  panel  with  a 
rule  graduated  to  1/16  inch. 

APPARATUS  FOR  FURNACE  PRESSURE  MEAS- 
UREMENTS: 

The  apparatus  for  measuring  the  fire  pressures  within  the 
furnace  consists  of  a differential  draft  gauge  connected  to  the 
combustion  chamber  by  piping.  The  gauge  is  provided  with  a 
scale  reading  in  1/100  in.  water  column. 

APPARATUS  FOR  APPLYING  HOSE  STREAMS: 

The  apparatus  used  in  the  hose  Stream  Tests  consists  of  a 
specigil  hydrant  at  the  back  of  and  to  one  side  of  the  test  furnace, 
a flexible  play  pipe  and  nozzle  attached  to  the  hydrant,  a gate 
valve  for  controlling  the  stream,  and  a pressure  gauge  at  the 
base  of  the  nozzle.  The  tip  of  the  nozzle  is  located  20  ft.  from 
the  test  panel  when  it  is  pulled  out  from  the  test  furnace. 

The  hydrant  is  connected  to  a water  main  in  a trench  under 
the  floor  and  is  supplied  by  three  4,500-gal.  pressure  tanks,  or  by 
an  electrically-driven  fire  pump  having  a capacity  of  500  gal. 
per  min.  located  in  another  building. 


109 


APPENDIX  VI 


UNDERWRITERS’  LABORATORIES’  STANDARD 
EQUIPMENT  FOR  TESTS  OF  FLOOR  AND 
CEILING  CONSTRUCTION. 

GENERAL  CHARACTER: 

The  equipment  for  the  tests  of  floors  and  ceilings  consists  of 
the  apparatus  used  for  the  Fire  and  Fire  and  Hose  Stream  Tests. 

The  standard  test  panels  consist  of  at  least  one  panel  of  stand- 
ard size  for  each  of  the  tests,  made  of  the  materials  under  inves- 
tigation and  seasoned  until  in  normal  condition. 

The  equipment  with  the  exception  of  some  of  the  apparatus 
used  in  the  tests  of  materials,  is  located  in  a buildijig  specially 
designed  for  work  of  this  character  and  known  as  West  Floor 
Furnace. 

FIRE  AND  HOSE  STREAM  TESTS 

The  equipment  used  in  these  tests  consists  of  the  furnace  in 
which  the  test  panels  are  subjected  to  fire,  the  apparatus  for 
measuring  the  temperatures  in  the  furnace,  and  the  sample,  the 
transmission  of  heat  through  the  panels,  the  apparatus  for 
measuring  the  deflections  of  the  panels,  the  gauge  for  measuring 
the  fire  pressures  in  the  furnace,  and  the  hydrant  and  nozzle 
by  means  of  which  the  stream  of  water  is  applied  in  the  Fire 
and  Hose  Stream  Tests. 

STANDARD  TEST  PANELS: 

The  standard  test  panels  are  13  ft.  7 in.  wide  and  17  ft.  11  in. 
long  in  which  the  materials  under  investigation  are  installed  as 
nearly  as  possible  in  the  manner  advocated  by  the  submitter. 
The  panels  are  mounted  in  the  restraining  frame  of  the  test 
furnace. 

STANDARD  TEST  FURNACE: 

The  furnace  proper  consists  of  a shallow  combustion  cham- 
ber approximately  12  ft.  wide  and  16  ft.  long  and  38  in.  deep. 
The  combustion  chamber  is  enclosed  by  a solid  brick  wall  along 
each  end  and  by  two  removable  gypsum  walls  at  each  side.  The 
removable  walls  are  suspended  on  a steel  beam.  Each  end  of 
the  furnace  is  provided  with  two  vents  leading  to  two  stacks. 
Each  end  wall  of  the  furnace  is  provided  with  three  observation 
holes  and  each  removable  gypsum  wall  with  two  observation 
holes  glazed  with  mica  and  so  arranged  that  all  parts  of  the 
interior  of  the  combustion  chamber  and  exposed  face  of  the  test 
panel  may  be  observed. 


no 


EQUIPMENT  FOR  FLOOR  TESTS 


The  furnace  is  heated  by  means  of  39  blast  burners  ^mounted 
in  the  floor  of  the  furnace  chamber.  The  burners  are  supplied 
with  gas  and  air  through  mixing  tubes. 

The  flow  of  gas  and  air  to  each  burner  is  regulated  by  indi- 
vidual valves  provided  with  graduated  scales  so  that  the  valve 
settings  may  be  duplicated  accurately. 

The  gas  is  supplied  to  the  furnace  through  a 6 in.  pipe  con- 
nected directly  to  the  street  mains  throu'gh  a meter.  Air  is 
supplied  to  the  burners  by  a blower  driven  by  an  electric  motor. 
The  entire  gas  and  air  supplies  are  controlled  by  valves  in  the 
main  connections. 

APPARATUS  FOR  TEMPERATURE  MEASURE- 
MENTS: 

The  apparatus  for  measuring  the  temperatures  within  the 
furnace  consists  of  six  thermo-couples  symmetrically  distributed 
under  the  exposed  surface  of  the  test  sample,  the  instruments 
for  indicating  temperatures,  and  a switchboard  and  connections 
for  placing  the  thermo-couples  in  circuit  with  the  instruments. 
The  thermo-couples  are  inserted  through  openings  in  the  brick 
floor  of  the  furnace  and  located  6 in.  from  the  face  of  the  test 
sample.  Provision  is  also  made  for  measuring  temperatures  in 
the  sample. 

APPARATUS  FOR  DEFLECTION  MEASUREMENTS: 

The  apparatus  for  measuring  deflections  on  the  unexposed 
face  of  the  test  panel  during  the  test  consists  of  vertical  targets 
symmetrically  distributed  over  the  unexposed  face  of  the  test 
sample  and  a surveyors  level  located  at  one  side  of  the  sample. 
The  targets  are  about  36  in.  in  length  provided  with  a scale 
graduated  to  1/10  of  an  inch  and  project  at  right  angles  to  the 
unexposed  surface  of  the  test  sample  to  which  they  are  rigidly 
attached.  The  surveyors  level  is  located  at  a convenient-  dis- 
tance from  the  panel  so  that  all  scales  in  the  targets  are  within 
the  range  of  the  telescope ; it  is  lined  up  so  that  the  telescope 
reads  about  2 in.  above  the  bottom  of  the  scale  on  the  targets. 

APPARATUS  FOR  FURNACE  PRESSURE  MEAS- 
UREMENTS: 

The  apparatus  for  measuring  the  fire  pressures  within  the 
furnace  consists  of  a differential  draft  gauge  connected  to  the 
combustion  chamber  by  piping.  The  gauge  is  provided  with  a 
scale  reading  1/100-in.  water  column.  _ 


111 


APPENDIX  VI— UNDERWRITERS’  LABORATORIES 


APPARATUS  FOR  APPLYING  FIRE  STREAMS: 

The  apparatus  used  in  the  Fire  Stream  Tests  consists  of  a 
special  hydrant  at  the  back  of  and  to  one  side  of  the  test  furnace, 
a flexible  play  pipe  and  nozzle  attached  to  the  hydrant,  a gate 
valve  for  controlling  the  stream,  and  a pressure  gauge  at  the 
hydrant.  The  tip  of  the  nozzle  is  located  12  ft.  from  the  test 
panel. 

The  hydrant  is  connected  to  a water  main  and  is  supplied 
by  three  4,500-gal.  pressure  tanks,  or  by  an  electrically-driven 
Are  pump  having  a capacity  of  500  gal.  per  min.  located  in 
another  building. 


) 


APPENDIX  VII 
STANDARD  SPECIFICATIONS 

for 

FIRE  TESTS  OF  MATERIALS  AND  CONSTRUCTION 

CONTROL  OF  FIRE  TESTS 

1.  The  conduct  of  fire  tests  of  materials  and  construction 
shall  be  controlled  by  the  standard  time-temperature  control 
curve  shown  in  Fig.  A.  The  points  on  the  curve  which  deter- 
mine its  character  are: 

1,000°  F.  at  5 minutes 
1,300°  F.  at  10  minutes 
1,550°  F.  at  30  minutes 
1,700°  F.  at  1 hour 
1,850°  F.  at  2 hours 
2,000°  F.  at  4 hours 
2,300°  F.  at  8 hours 


TIME  TEMPERATURE  CURVES 
UNDERWRITERS’  LABORATORIES 

113 


APPENDIX  VII— TEST  SPECIFICATIONS 


2.  (a)  The  temperature  fixed  by  the  curve  shall  be  deemed 
to  be  the  average  true  temperature  of  the  furnace  gases  as 
obtained  from  the  readings  of  several  thermo-couples  (not  less 
than  three)  symmetrically  disposed  and  distributed  in  such  a 
manner  as  to  show  the  temperatures  of  the  gases  near  all  parts 
of  the  sample. 

(b)  The  temperatures  shall  be  read  at  intervals  not  exceeding 
5 min.  during  the  first  hour,  and  thereafter  the  intervals  may  be 
increased  to  not  more  than  15  min. 

CLASSIFICATION  AS  DETERMINED  BY  TEST 

3.  (a)  Fire-resistive  materials  and  construction  shall  be 
classified  in  accordance  with  the  degree  of  protection  they  af¥ord 
when  measured  by  a fire  test  conducted  in  conformity  with  the 
standard  time-temperature  control  curve  as : 

4-hour  Protection 
2-hour  Protection 
1-hour  Protection 
^-hour  Protection 
^-hour  Protection 

(b)  Other  classes  may  be  interpolated  or  added  as  needed. 

TEST  STRUCTURES 

4.  (a)  The  test  structure  may  be  located  at  any  place  where 
all  the  necessary  facilities  for  properly  conducting  the  test  are 
provided. 

(b)  Entire  freedom  is  left  to  each  investigator  in  the  design 
of  his  test  structure  and  the  nature  and  use  of  fuel,  provided 
the  test  requirements  are  met. 

TEST  SAMPLES 

5.  The  material  or  construction  constituting  the  test  sample 
shall  be  truly  representative  of  the  regular  practice. 

CONDUCT  OF  FIRE  TESTS 

6.  The  fire  test  on  the  sample  with  its  applied  load,  if  any, 
shall  be  continued  until  failure  occurs,  or  until  it  has  withstood 
the  test  conditions  for  a period  equal  to  times  that  for  wnich 
classification  is  desired. 

7.  A second  test  with  duplicate  sample  shall  be  made  to 
determine  the  effect  of  a hose  stream  on  a sample  under  fire 
test,  the  water  being  applied  at  the  end  of  a period  equal  to 
three-fourths  of  that  for  which  classification  is  desired,  but  not 
later  than  one  hour  after  the  beginning  of  the  test;  except  that 
for  classification  periods  of  one-half  hour  or  less  the  fire  stream 
test  may  be  omitted. 

8.  The  size  of  nozzle,  water  pressure  and  time  of  water 


114 


FIRE  TESTS 


application  shall  be  as  indicated  in  Table  I.  The  hose  stream 
shall  be  first  directed  at  the  middle  of  the  sample  and  then  at 
all  parts  of  the  exposed  faces,  changes  in  direction  being  made 
slowly. 

9.  For  any  material  or  construction  intended  to  carry  load 
other  than  its  own  weight,  the  full  rated  safe  working  load  shall 
be  applied  during  the  entire  fire  test,  also  during  the  fire  stream 
test.  After  completion  of  the  fire  stream  test,  the  sample  shall 
be  subjected  to  excess  loading  as  prescribed  under  specifications 
for  the  different  structural  parts. 

FLOOR  AND  ROOF  TESTS 

10.  For  floor  and  roof  tests  the  sample  shall  be  of  such  a 
size  that  the  minimum  span  of  the  supporting  beams  of  the 
floor  arch  shall  be  12  ft.,  and  the  supporting  beams  and  girders 
shall  have  a clearance  of  at  least  8 in.  from  the  walls  of  the 
test  structure. 

11.  The  floor  or  roof  may  be  tested  as  soon  after  construc- 
tion as  desired,  but  within  40  days.  Artificial  drying  will  be 
allowed  if  desired. 

12.  If  the  construction  is  to  be  plastered  in  practice,  the 
sample  shall  be  plastered  in  the  same  manner. 

13.  The  floor  or  roof  shall  be  loaded  in  a manner  to  develop 
in  each  member  of  the  construction  stresses  equal  to  the  maxi- 
mum safe  working  stress  allowed  in  the  material  of  the  member. 

14.  The  test  shall  not  be  regarded  as  successful  unless  the 
following  conditions  are  met: 

(a)  The  floor  or  roof  shall  have  sustained  safely  the  full 
rated  safe  working  load  during  the  fire  test  without  passage  of 
flame,  for  a period  equal  to  lj4  times  that  for  which  classification 
is  desired. 

(b)  The  floor  or  roof  shall  have  sustained  safely  the  full 
rated  safe  working  load  during  the  fire  stream  test  as  prescribed 
in  Sections  7 and  8,  without  passage  of  flame,  and  after  its  com- 
pletion shall  sustain  a total  load  equal  to  the  dead  load  plus 
2^/2  times  the  live  load  for  which  the  construction  is  designed. 

NON-BEARING  PARTITION  TESTS 

15.  For  partition  tests  the  area  of  the  sample  shall  be  not 
less  than  100  sq.  ft.  and  no  dimension  less  than  9 ft. 

16.  Temperatures  on  the  outer  surface  of  the  partition  shall 
be  read  by  not  less  than  five  thermometers,  symmetrically  dis- 
posed and  placed  against  the  surface  of  the  partition  with  their 
bulbs  properly  protected  against  radiation  of  heat. 

17.  The  distance  of  the  nozzle  from  the  partition  during  the 
application  of  water  shall  be  not  more  than  20  ft.  when  the  hose 
stream  is  applied  approximately  normal  to  the  surface  of  the 


115 


FIRE  TESTS 


partition,  which  distance  shall  be  reduced  by  1 ft.  for  each 
deviation  of  10  deg.  of  angle  from  the  normal  when  the  hose 
stream  is  applied  at  an  angle  to  the  surface  of  the  partition. 

18.  The  test  shall  not  be  regarded  as  successful  unless  the 
following  conditions  are  met: 

(a)  The  partition  shall  have  withstood  safely  the  fire  test 
for  a period  equal  to  1^  times  that  for  which  classification  is 
desired. 

(b)  The  partition  shall  have  withstood  the  fire  stream  test 
as  prescribed  in  Sections  7 and  8. 

(c)  No  flame  shall  have  passed  through  the  partition  during 
the  prescribed  fire  period. 

(d)  Transmission  of  heat  through  the  partition  during  the 
prescribed  fire  period  shall  not  have  been  such  as  to  raise  the 
temperature  on  its  outer  surface  in  excess  of  300°  F. 

(e)  The  partition  shall  not  have  warped  or  bulged  or  disinte- 
grated, under  the  action  of  fire  or  water  to  such  an  extent  as  to 
be  unsafe. 


TABLE  I 


Size  of 

Water  Time  of 

Parts  of  Structure 

Type  of 
Protection 

Hose 

Nozzle 

Pressure  Appli- 
Nozzle  cation 

In. 

Lb. 

Min. 

4-hour 

50 

10 

2-hour 

IVs 

50 

5 

Floor  and  Roofs i 

1-hour 

m 

50 

2.5 

^-hour 

1/8 

30 

1 

' ^-hour 

1/8  , 

15 

1 

4-hour 

1/ 

50 

5 

Walls,  Columns  and 

,2-hour 

1-hour 

1/ 

1/ 

1/8 

30 

3 

30 

2.5 

Partitions 

y^-houv 

30 

1 

34-hour 

1/8 

15 

1 

116 


SECTION  V 


RECOMMENDATIONS 


TO  THE  FIRE  COUNCIL  OF  UNDERWRITERS’  LABORATORIES: 

We  recommend  promulgation  of  the  following  notices  to  subscrib- 
ers and  the  action  indicated  thereby; 

Guide  No.  40  UC.  16.  3 (Corridor  Partitions)  August  10,  1922. 

40  UC.  16.18  (Room  Partitions)  Lab.  File  R.  1355. 

40  UC.  16.22  (Vertical  Communications) 

Associated  Metal  Lath  Manufacturers, 

Chicago,  111. 

National  Lumber  Manufacturers  Association, 

Chicago,  111..  Washington,  D.  C. 

Metal  Lath  and  Gypsum  Plaster  on  Wood  Studs:  Interior  Bearing, 
Corridor,  and  Room  Partitions  and  Walls  and 
Vertical  Shaft  Enclosures. 


^ Submitters 


Bearing  partitions,  walls  or  enclosures  of  wood  studs,  2 by  4 in.  or 
larger,  spaced  16  in.  centers  effectively  fire  stopped,  finished  on 
each  side  with  in.  diamond  mesh  expanded  metal  lath,  cut  from 
not  less  than  No.  26  U.  S.  gauge  steel,  and  weighing  not  less  than 
2.5  lbs.  per  sq.  yd.  attached  to  supports  by  not  less  than  1^  in., 
4 penny  nails  or  in.,  14  gauge  wire  staples  spaced  not  to  exceed 
6 in.  on  center;  and  ^ in.  three-coat  wood  fibered  or  sanded  gyp- 
sum plaster.  Metal  lath  lapped  at  all  joints  with  walls,  ceilings 
or  other  partitions;  wood  or  metal  trim  and  standing  finish  se- 
cured to  spot  grounds. 

Intended  for  use  on  the  inside  of  buildings  of  frame  or  ordinary  con- 
struction with  live  loads  carried  by  this  construction  up  to  50  lbs. 
per  sq.  ft.  and  when  permitted  by  local  rules. 

Inspection  departments  having  jurisdiction  to  be  consulted  before  in- 
stallation. 

CLASSIFICATION  Rlhr. 

Listed — Fire. 

REEXAMINATION  SERVICE. 


117 


RECOMMENDATIONS 


Guide  No.  40  UC.  16.  3 (Corridor  Partitions)  August  10,  1922. 

40  UC.  16.18  (Room  Partitions)  Lab.  File  R.  1355. 

40  UC.  16.22  (Vertical  Communications) 

Associated  Metal  Lath  Manufacturers, 

Chicago,  111. 

National  Lumber  Manufacturers  Association, 

Chicago,  111.  Washington,  D.  C. 

\ 

Metal  Lath  and  Gypsum  Plaster  on  Wood  Studs:  Interior  Non- 
Bearing  Corridor,  and  Room  Partitions  and  Walls 
Vertical  Shaft  Enclosures. 


Submittors 


Non-bearing  partitions,  walls,  or  enclosures  of  wood  studs,  2 by  2 in., 
2 by  4 in.  or  larger,  spaced  16  in.  centers;  effectively  fire  stopped 
and  finished  on  each  side  with  ^ in.  diamond  mesh  expanded  metal 
lath  cut  from  not  less  than  No.  26  U.  S.  gauge  steel,  weighing  not 
less  than  2.5  lbs.  per  sq.  yd.  attached  to  supports  by  not  less  than 
in.,  4 penny  nails  or  in.,  14  gauge  wire  staples  spaced  not 
to  exceed  6 in.  on  center;  and  ^ in.  three-coat  wood  fibered  or 
sanded^  gypsum  plaster.  Metal  lath  lapped  at  all  joints  with  walls 
and  ceilings  or  partitions,  wood  or  metal  trim  and  standing  finish 
secured  to  spot  grounds. 

Intended  for  the  sub-division  of  floor  areas  in  buildings  of  frame  or 
ordinary  construction  and  in  buildings  of  superior  constructon  in 
which  partitions  having  combustible  supports  are  allowed. 

Inspection  departments  having  jurisdiction  to  be  consulted  before  in- 
stallation. 

CLASSIFICATION  Rlhr. 

Listed — Fire. 

REEXAMINATION  SERVICE. 


118 


RECOMMENDATIONS 


Guide  No.  40  UC  9 August  10,  1922 — Laboratories’  File  R.  1355. 

Associated  Metal  Lath  Manufacturers, 

Chicago,  111. 

National  Lumber  Manufacturers  Association, 

Chicago,  111.  Washington,  D.  C. 

Metal  Lath  and  Gypsum  Plaster  on  Wood  Supports:  'Interior, 

Single,  Wall,  Partition  and  Ceiling  Finish. 

Interior  finish  of  the  built-up  type,  consisting  of  ^ in.  diamond  mesh 
expanded  metal  lath  cut  from  not  less  than  No.  26  U.  S.  gauge 
steel,  weighing  not  less  than  2.5  lbs.  per  sq.  yd.  for  walls  and  par- 
titions and  not  less  than  No.  25  U.  S.  gauge  steel  weighing  not 
less  than  3 lbs.  per  sq.  yd.  for  ceilings,  attached  to  joists  by  not 
less  than  2 in.,  6 penny  nails  spaced  not  to  exceed  6 in.  on  center, 
or  by  equivalent  staples,  or  to  studs  by  not  less  than  lJ/2  in.  4 
penny  nails  or  1^  in.,  14  gauge  wire  staples  spaced  not  to  exceed 
6 in.  on  center;  and  in.  three-coat  wood  fibered  or  sanded  gyp- 
sum plaster. 

Intended  for  use  on  walls,  ceilings,  and  partitions  on  the  interior  of 
buildings  of  frame  or  ordinary  construction. 

Inspection  departments  having  jurisdiction  to  be  consulted  before  in- 
stallation. 

CLASSIFICATION:  Single  finish  on  walls,  partitions,  and  ceiliners 
R30m  (rating  applies  only  when  exposed  from  the  finished  face). 

Listed — Fire. 


Submitters 


REEXAMINATION  SERVICE. 


Guide  No.  40  UC  6 August  10,  1922 — Laboratories’  File  R.  1355. 

Combustible  Floors 

The  great  value  in  safeguarding  life  and  property  of  floors  as  fire 
stops,  preventing  the  vertical  spread  of  fire  within  buildings  makes 
it  essential  that  all  floors  be  of  materials,  design  and  construction 
developing  a high  degree  of  fire  resistance,  and  with  partitions  of  a 
similar  resistance,  fire  can  frequently  be  confined  to  the  room  of 
origin.  Floors  should  have  a minimum  number  of  vertical  open- 
ings and^  these  should  be  protected  by  standard  retardants  of  a 
rating  suitable  for  the  exposure. 

The  “R”  (fire  retardant)  ratings  for  floor  constructions  given  in  the 
following  cards  are  based  upon  the  performance  of  these  construc- 
tions under  the  Standard  Fire  Endurance  and  Fire  and  Hose 
Stream  Tests  which  are  judged  equivalent  to  severe  fire  exposure 
conditions.  Only  floors  rated  not  lower  than  the  probable  fire 
exposure  should  be  used. 

Inspection  authorities  having  jurisdiction  should  be  consulted  in  all 
cases.  , 


119 


